diff --git a/conf/app.ini b/conf/app.ini
index 43033eaa66..c90246005c 100644
--- a/conf/app.ini
+++ b/conf/app.ini
@@ -72,6 +72,14 @@ FROM =
 USER = 
 PASSWD = 
 
+[oauth]
+ENABLED = false
+
+[oauth.github]
+ENABLED =
+CLIENT_ID = 
+CLIENT_SECRET = 
+
 [cache]
 ; Either "memory", "redis", or "memcache", default is "memory"
 ADAPTER = memory
diff --git a/gogs.go b/gogs.go
index e719748200..df268980f5 100644
--- a/gogs.go
+++ b/gogs.go
@@ -19,7 +19,7 @@ import (
 // Test that go1.2 tag above is included in builds. main.go refers to this definition.
 const go12tag = true
 
-const APP_VER = "0.2.2.0406 Alpha"
+const APP_VER = "0.2.2.0407 Alpha"
 
 func init() {
 	base.AppVer = APP_VER
diff --git a/models/user.go b/models/user.go
index a5a6de097f..0fcf72437e 100644
--- a/models/user.go
+++ b/models/user.go
@@ -366,6 +366,19 @@ func GetUserByName(name string) (*User, error) {
 	return user, nil
 }
 
+// GetUserEmailsByNames returns a slice of e-mails corresponds to names.
+func GetUserEmailsByNames(names []string) []string {
+	mails := make([]string, 0, len(names))
+	for _, name := range names {
+		u, err := GetUserByName(name)
+		if err != nil {
+			continue
+		}
+		mails = append(mails, u.Email)
+	}
+	return mails
+}
+
 // GetUserByEmail returns the user object by given e-mail if exists.
 func GetUserByEmail(email string) (*User, error) {
 	if len(email) == 0 {
diff --git a/modules/base/conf.go b/modules/base/conf.go
index 0a618ab1d2..ba9c320d77 100644
--- a/modules/base/conf.go
+++ b/modules/base/conf.go
@@ -22,13 +22,21 @@ import (
 	"github.com/gogits/gogs/modules/log"
 )
 
-// Mailer represents a mail service.
+// Mailer represents mail service.
 type Mailer struct {
 	Name         string
 	Host         string
 	User, Passwd string
 }
 
+// Oauther represents oauth service.
+type Oauther struct {
+	GitHub struct {
+		Enabled                bool
+		ClientId, ClientSecret string
+	}
+}
+
 var (
 	AppVer       string
 	AppName      string
@@ -45,8 +53,9 @@ var (
 	CookieUserName     string
 	CookieRememberName string
 
-	Cfg         *goconfig.ConfigFile
-	MailService *Mailer
+	Cfg          *goconfig.ConfigFile
+	MailService  *Mailer
+	OauthService *Oauther
 
 	LogMode   string
 	LogConfig string
@@ -206,15 +215,17 @@ func newSessionService() {
 
 func newMailService() {
 	// Check mailer setting.
-	if Cfg.MustBool("mailer", "ENABLED") {
-		MailService = &Mailer{
-			Name:   Cfg.MustValue("mailer", "NAME", AppName),
-			Host:   Cfg.MustValue("mailer", "HOST"),
-			User:   Cfg.MustValue("mailer", "USER"),
-			Passwd: Cfg.MustValue("mailer", "PASSWD"),
-		}
-		log.Info("Mail Service Enabled")
+	if !Cfg.MustBool("mailer", "ENABLED") {
+		return
 	}
+
+	MailService = &Mailer{
+		Name:   Cfg.MustValue("mailer", "NAME", AppName),
+		Host:   Cfg.MustValue("mailer", "HOST"),
+		User:   Cfg.MustValue("mailer", "USER"),
+		Passwd: Cfg.MustValue("mailer", "PASSWD"),
+	}
+	log.Info("Mail Service Enabled")
 }
 
 func newRegisterMailService() {
@@ -239,6 +250,25 @@ func newNotifyMailService() {
 	log.Info("Notify Mail Service Enabled")
 }
 
+func newOauthService() {
+	if !Cfg.MustBool("oauth", "ENABLED") {
+		return
+	}
+
+	OauthService = &Oauther{}
+	oauths := make([]string, 0, 10)
+
+	// GitHub.
+	if Cfg.MustBool("oauth.github", "ENABLED") {
+		OauthService.GitHub.Enabled = true
+		OauthService.GitHub.ClientId = Cfg.MustValue("oauth.github", "CLIENT_ID")
+		OauthService.GitHub.ClientSecret = Cfg.MustValue("oauth.github", "CLIENT_SECRET")
+		oauths = append(oauths, "GitHub")
+	}
+
+	log.Info("Oauth Service Enabled %s", oauths)
+}
+
 func NewConfigContext() {
 	//var err error
 	workDir, err := ExecDir()
@@ -303,4 +333,5 @@ func NewServices() {
 	newMailService()
 	newRegisterMailService()
 	newNotifyMailService()
+	newOauthService()
 }
diff --git a/modules/base/markdown.go b/modules/base/markdown.go
index f0992d04df..ce1e2f5bec 100644
--- a/modules/base/markdown.go
+++ b/modules/base/markdown.go
@@ -90,21 +90,21 @@ func (options *CustomRender) Link(out *bytes.Buffer, link []byte, title []byte,
 }
 
 var (
-	mentionPattern    = regexp.MustCompile(`@[0-9a-zA-Z_]{1,}`)
+	MentionPattern    = regexp.MustCompile(`@[0-9a-zA-Z_]{1,}`)
 	commitPattern     = regexp.MustCompile(`(\s|^)https?.*commit/[0-9a-zA-Z]+(#+[0-9a-zA-Z-]*)?`)
 	issueFullPattern  = regexp.MustCompile(`(\s|^)https?.*issues/[0-9]+(#+[0-9a-zA-Z-]*)?`)
-	issueIndexPattern = regexp.MustCompile(`(\s|^)#[0-9]+`)
+	issueIndexPattern = regexp.MustCompile(`#[0-9]+`)
 )
 
 func RenderSpecialLink(rawBytes []byte, urlPrefix string) []byte {
-	ms := mentionPattern.FindAll(rawBytes, -1)
+	ms := MentionPattern.FindAll(rawBytes, -1)
 	for _, m := range ms {
 		rawBytes = bytes.Replace(rawBytes, m,
 			[]byte(fmt.Sprintf(`<a href="/user/%s">%s</a>`, m[1:], m)), -1)
 	}
 	ms = commitPattern.FindAll(rawBytes, -1)
 	for _, m := range ms {
-		m = bytes.TrimPrefix(m, []byte(" "))
+		m = bytes.TrimSpace(m)
 		i := strings.Index(string(m), "commit/")
 		j := strings.Index(string(m), "#")
 		if j == -1 {
@@ -115,7 +115,7 @@ func RenderSpecialLink(rawBytes []byte, urlPrefix string) []byte {
 	}
 	ms = issueFullPattern.FindAll(rawBytes, -1)
 	for _, m := range ms {
-		m = bytes.TrimPrefix(m, []byte(" "))
+		m = bytes.TrimSpace(m)
 		i := strings.Index(string(m), "issues/")
 		j := strings.Index(string(m), "#")
 		if j == -1 {
@@ -126,9 +126,8 @@ func RenderSpecialLink(rawBytes []byte, urlPrefix string) []byte {
 	}
 	ms = issueIndexPattern.FindAll(rawBytes, -1)
 	for _, m := range ms {
-		m = bytes.TrimPrefix(m, []byte(" "))
 		rawBytes = bytes.Replace(rawBytes, m, []byte(fmt.Sprintf(
-			` <a href="%s/issues/%s">%s</a>`, urlPrefix, m[1:], m)), -1)
+			`<a href="%s/issues/%s">%s</a>`, urlPrefix, m[1:], m)), -1)
 	}
 	return rawBytes
 }
diff --git a/modules/mailer/mail.go b/modules/mailer/mail.go
index eee6b916ca..d2bf1310a0 100644
--- a/modules/mailer/mail.go
+++ b/modules/mailer/mail.go
@@ -111,11 +111,11 @@ func SendResetPasswdMail(r *middleware.Render, user *models.User) {
 	SendAsync(&msg)
 }
 
-// SendNotifyMail sends mail notification of all watchers.
-func SendNotifyMail(user, owner *models.User, repo *models.Repository, issue *models.Issue) error {
+// SendIssueNotifyMail sends mail notification of all watchers of repository.
+func SendIssueNotifyMail(user, owner *models.User, repo *models.Repository, issue *models.Issue) ([]string, error) {
 	watches, err := models.GetWatches(repo.Id)
 	if err != nil {
-		return errors.New("mail.NotifyWatchers(get watches): " + err.Error())
+		return nil, errors.New("mail.NotifyWatchers(get watches): " + err.Error())
 	}
 
 	tos := make([]string, 0, len(watches))
@@ -126,20 +126,37 @@ func SendNotifyMail(user, owner *models.User, repo *models.Repository, issue *mo
 		}
 		u, err := models.GetUserById(uid)
 		if err != nil {
-			return errors.New("mail.NotifyWatchers(get user): " + err.Error())
+			return nil, errors.New("mail.NotifyWatchers(get user): " + err.Error())
 		}
 		tos = append(tos, u.Email)
 	}
 
 	if len(tos) == 0 {
-		return nil
+		return tos, nil
 	}
 
 	subject := fmt.Sprintf("[%s] %s", repo.Name, issue.Name)
 	content := fmt.Sprintf("%s<br>-<br> <a href=\"%s%s/%s/issues/%d\">View it on Gogs</a>.",
-		issue.Content, base.AppUrl, owner.Name, repo.Name, issue.Index)
+		base.RenderSpecialLink([]byte(issue.Content), owner.Name+"/"+repo.Name),
+		base.AppUrl, owner.Name, repo.Name, issue.Index)
 	msg := NewMailMessageFrom(tos, user.Name, subject, content)
-	msg.Info = fmt.Sprintf("Subject: %s, send notify emails", subject)
+	msg.Info = fmt.Sprintf("Subject: %s, send issue notify emails", subject)
+	SendAsync(&msg)
+	return tos, nil
+}
+
+// SendIssueMentionMail sends mail notification for who are mentioned in issue.
+func SendIssueMentionMail(user, owner *models.User, repo *models.Repository, issue *models.Issue, tos []string) error {
+	if len(tos) == 0 {
+		return nil
+	}
+
+	issueLink := fmt.Sprintf("%s%s/%s/issues/%d", base.AppUrl, owner.Name, repo.Name, issue.Index)
+	body := fmt.Sprintf(`%s mentioned you.`)
+	subject := fmt.Sprintf("[%s] %s", repo.Name, issue.Name)
+	content := fmt.Sprintf("%s<br>-<br> <a href=\"%s\">View it on Gogs</a>.", body, issueLink)
+	msg := NewMailMessageFrom(tos, user.Name, subject, content)
+	msg.Info = fmt.Sprintf("Subject: %s, send issue mention emails", subject)
 	SendAsync(&msg)
 	return nil
 }
diff --git a/modules/oauth2/oauth2.go b/modules/oauth2/oauth2.go
index 6612b95a81..180c52ca0a 100644
--- a/modules/oauth2/oauth2.go
+++ b/modules/oauth2/oauth2.go
@@ -29,13 +29,13 @@ import (
 
 	"github.com/gogits/session"
 
+	"github.com/gogits/gogs/modules/log"
 	"github.com/gogits/gogs/modules/middleware"
 )
 
 const (
-	codeRedirect = 302
-	keyToken     = "oauth2_token"
-	keyNextPage  = "next"
+	keyToken    = "oauth2_token"
+	keyNextPage = "next"
 )
 
 var (
@@ -179,42 +179,49 @@ var LoginRequired martini.Handler = func() martini.Handler {
 		token := unmarshallToken(ctx.Session)
 		if token == nil || token.IsExpired() {
 			next := url.QueryEscape(ctx.Req.URL.RequestURI())
-			ctx.Redirect(PathLogin+"?next="+next, codeRedirect)
+			ctx.Redirect(PathLogin + "?next=" + next)
+			return
 		}
 	}
 }()
 
 func login(t *oauth.Transport, ctx *middleware.Context) {
-	next := extractPath(ctx.Req.URL.Query().Get(keyNextPage))
+	next := extractPath(ctx.Query(keyNextPage))
 	if ctx.Session.Get(keyToken) == nil {
 		// User is not logged in.
-		ctx.Redirect(t.Config.AuthCodeURL(next), codeRedirect)
+		ctx.Redirect(t.Config.AuthCodeURL(next))
 		return
 	}
 	// No need to login, redirect to the next page.
-	ctx.Redirect(next, codeRedirect)
+	ctx.Redirect(next)
 }
 
 func logout(t *oauth.Transport, ctx *middleware.Context) {
-	next := extractPath(ctx.Req.URL.Query().Get(keyNextPage))
+	next := extractPath(ctx.Query(keyNextPage))
 	ctx.Session.Delete(keyToken)
-	ctx.Redirect(next, codeRedirect)
+	ctx.Redirect(next)
 }
 
 func handleOAuth2Callback(t *oauth.Transport, ctx *middleware.Context) {
-	next := extractPath(ctx.Req.URL.Query().Get("state"))
-	code := ctx.Req.URL.Query().Get("code")
+	if errMsg := ctx.Query("error_description"); len(errMsg) > 0 {
+		log.Error("oauth2.handleOAuth2Callback: %s", errMsg)
+		return
+	}
+
+	next := extractPath(ctx.Query("state"))
+	code := ctx.Query("code")
 	tk, err := t.Exchange(code)
 	if err != nil {
 		// Pass the error message, or allow dev to provide its own
 		// error handler.
-		ctx.Redirect(PathError, codeRedirect)
+		log.Error("oauth2.handleOAuth2Callback(token.Exchange): %v", err)
+		// ctx.Redirect(PathError)
 		return
 	}
 	// Store the credentials in the session.
 	val, _ := json.Marshal(tk)
 	ctx.Session.Set(keyToken, val)
-	ctx.Redirect(next, codeRedirect)
+	ctx.Redirect(next)
 }
 
 func unmarshallToken(s session.SessionStore) (t *token) {
diff --git a/routers/repo/issue.go b/routers/repo/issue.go
index 38522e0c70..9688fd4d94 100644
--- a/routers/repo/issue.go
+++ b/routers/repo/issue.go
@@ -9,6 +9,7 @@ import (
 	"net/url"
 	"strings"
 
+	"github.com/Unknwon/com"
 	"github.com/go-martini/martini"
 
 	"github.com/gogits/gogs/models"
@@ -99,7 +100,7 @@ func CreateIssue(ctx *middleware.Context, params martini.Params, form auth.Creat
 	issue, err := models.CreateIssue(ctx.User.Id, ctx.Repo.Repository.Id, form.MilestoneId, form.AssigneeId,
 		ctx.Repo.Repository.NumIssues, form.IssueName, form.Labels, form.Content, false)
 	if err != nil {
-		ctx.Handle(200, "issue.CreateIssue", err)
+		ctx.Handle(200, "issue.CreateIssue(CreateIssue)", err)
 		return
 	}
 
@@ -107,14 +108,31 @@ func CreateIssue(ctx *middleware.Context, params martini.Params, form auth.Creat
 	if err = models.NotifyWatchers(&models.Action{ActUserId: ctx.User.Id, ActUserName: ctx.User.Name, ActEmail: ctx.User.Email,
 		OpType: models.OP_CREATE_ISSUE, Content: fmt.Sprintf("%d|%s", issue.Index, issue.Name),
 		RepoId: ctx.Repo.Repository.Id, RepoName: ctx.Repo.Repository.Name, RefName: ""}); err != nil {
-		ctx.Handle(200, "issue.CreateIssue", err)
+		ctx.Handle(200, "issue.CreateIssue(NotifyWatchers)", err)
 		return
 	}
 
-	// Mail watchers.
+	// Mail watchers and mentions.
 	if base.Service.NotifyMail {
-		if err = mailer.SendNotifyMail(ctx.User, ctx.Repo.Owner, ctx.Repo.Repository, issue); err != nil {
-			ctx.Handle(200, "issue.CreateIssue", err)
+		tos, err := mailer.SendIssueNotifyMail(ctx.User, ctx.Repo.Owner, ctx.Repo.Repository, issue)
+		if err != nil {
+			ctx.Handle(200, "issue.CreateIssue(SendIssueNotifyMail)", err)
+			return
+		}
+
+		tos = append(tos, ctx.User.LowerName)
+		ms := base.MentionPattern.FindAllString(issue.Content, -1)
+		newTos := make([]string, 0, len(ms))
+		for _, m := range ms {
+			if com.IsSliceContainsStr(tos, m[1:]) {
+				continue
+			}
+
+			newTos = append(newTos, m[1:])
+		}
+		if err = mailer.SendIssueMentionMail(ctx.User, ctx.Repo.Owner, ctx.Repo.Repository,
+			issue, models.GetUserEmailsByNames(newTos)); err != nil {
+			ctx.Handle(200, "issue.CreateIssue(SendIssueMentionMail)", err)
 			return
 		}
 	}
diff --git a/routers/user/social.go b/routers/user/social.go
index f5577d809b..08cfcd83f2 100644
--- a/routers/user/social.go
+++ b/routers/user/social.go
@@ -1,20 +1,20 @@
 // Copyright 2014 The Gogs Authors. All rights reserved.
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
+
 package user
 
 import (
 	"encoding/json"
 	"strconv"
 
+	"code.google.com/p/goauth2/oauth"
+
 	"github.com/gogits/gogs/models"
 	"github.com/gogits/gogs/modules/base"
 	"github.com/gogits/gogs/modules/log"
 	"github.com/gogits/gogs/modules/middleware"
-	//"github.com/gogits/gogs/modules/oauth2"
-
-	"code.google.com/p/goauth2/oauth"
-	"github.com/martini-contrib/oauth2"
+	"github.com/gogits/gogs/modules/oauth2"
 )
 
 type SocialConnector interface {
@@ -80,6 +80,10 @@ func SocialSignIn(ctx *middleware.Context, tokens oauth2.Tokens) {
 			Extra:        tokens.ExtraData(),
 		},
 	}
+	if len(tokens.Access()) == 0 {
+		log.Error("empty access")
+		return
+	}
 	var err error
 	var u *models.User
 	if err = gh.Update(); err != nil {
diff --git a/routers/user/user.go b/routers/user/user.go
index 12f2bd8c51..f6a39b86c7 100644
--- a/routers/user/user.go
+++ b/routers/user/user.go
@@ -78,6 +78,11 @@ func SignIn(ctx *middleware.Context, form auth.LogInForm) {
 	ctx.Data["Title"] = "Log In"
 
 	if ctx.Req.Method == "GET" {
+		if base.OauthService != nil {
+			ctx.Data["OauthEnabled"] = true
+			ctx.Data["OauthGitHubEnabled"] = base.OauthService.GitHub.Enabled
+		}
+
 		// Check auto-login.
 		userName := ctx.GetCookie(base.CookieUserName)
 		if len(userName) == 0 {
diff --git a/templates/issue/create.tmpl b/templates/issue/create.tmpl
index 01784cd21e..5375040b09 100644
--- a/templates/issue/create.tmpl
+++ b/templates/issue/create.tmpl
@@ -19,7 +19,7 @@
                     </div>
                     <ul class="nav nav-tabs" data-init="tabs">
                         <li class="active issue-write"><a href="#issue-textarea" data-toggle="tab">Write</a></li>
-                        <li class="issue-preview"><a href="#issue-preview" data-toggle="tab" data-ajax="/api/v1/markdown?repo=repo_id&issue=new" data-ajax-name="issue-preview" data-ajax-method="post" data-preview="#issue-preview">Preview</a></li>
+                        <li class="issue-preview"><a href="#issue-preview" data-toggle="tab" data-ajax="/api/v1/markdown?repoLink={{.RepoLink}}" data-ajax-name="issue-preview" data-ajax-method="post" data-preview="#issue-preview">Preview</a></li>
                     </ul>
                     <div class="tab-content">
                         <div class="tab-pane" id="issue-textarea">
diff --git a/templates/user/signin.tmpl b/templates/user/signin.tmpl
index 43f47e4121..eb4cb9ccee 100644
--- a/templates/user/signin.tmpl
+++ b/templates/user/signin.tmpl
@@ -43,9 +43,12 @@
             </div>
         </div>
 
+        {{if .OauthEnabled}}
         <div class="form-group text-center" id="social-login">
-            <a class="btn btn-danger btn-lg" href="/user/sign_up">Register new account</a>
+            <h4>Log In with Social Accounts</h4>
+            {{if .OauthGitHubEnabled}}<a href="/user/login/github"><i class="fa fa-github-square fa-3x"></i></a>{{end}}
         </div>
+        {{end}}
     </form>
 </div>
 {{template "base/footer" .}}
\ No newline at end of file
diff --git a/web.go b/web.go
index c8fb8dc093..8d53b9e1bc 100644
--- a/web.go
+++ b/web.go
@@ -20,16 +20,13 @@ import (
 	"github.com/gogits/gogs/modules/base"
 	"github.com/gogits/gogs/modules/log"
 	"github.com/gogits/gogs/modules/middleware"
-	//"github.com/gogits/gogs/modules/oauth2"
+	"github.com/gogits/gogs/modules/oauth2"
 	"github.com/gogits/gogs/routers"
 	"github.com/gogits/gogs/routers/admin"
 	"github.com/gogits/gogs/routers/api/v1"
 	"github.com/gogits/gogs/routers/dev"
 	"github.com/gogits/gogs/routers/repo"
 	"github.com/gogits/gogs/routers/user"
-
-	"github.com/martini-contrib/oauth2"
-	"github.com/martini-contrib/sessions"
 )
 
 var CmdWeb = cli.Command{
@@ -63,12 +60,17 @@ func runWeb(*cli.Context) {
 	m.Use(middleware.InitContext())
 
 	scope := "https://api.github.com/user"
-	oauth2.PathCallback = "/oauth2callback"
-	m.Use(sessions.Sessions("my_session", sessions.NewCookieStore([]byte("secret123"))))
+	// m.Use(sessions.Sessions("my_session", sessions.NewCookieStore([]byte("secret123"))))
+	// m.Use(oauth2.Github(&oauth2.Options{
+	// 	ClientId:     "09383403ff2dc16daaa1",
+	// 	ClientSecret: "5f6e7101d30b77952aab22b75eadae17551ea6b5",
+	// 	RedirectURL:  base.AppUrl + oauth2.PathCallback,
+	// 	Scopes:       []string{scope},
+	// }))
 	m.Use(oauth2.Github(&oauth2.Options{
-		ClientId:     "09383403ff2dc16daaa1",
-		ClientSecret: "5f6e7101d30b77952aab22b75eadae17551ea6b5",
-		RedirectURL:  base.AppUrl + oauth2.PathCallback,
+		ClientId:     "ba323b44192e65c7c320",
+		ClientSecret: "6818ffed53bea5815bf1a6412d1933f25fa10619",
+		RedirectURL:  base.AppUrl + oauth2.PathCallback[1:],
 		Scopes:       []string{scope},
 	}))
 
@@ -92,8 +94,8 @@ func runWeb(*cli.Context) {
 	m.Get("/avatar/:hash", avt.ServeHTTP)
 
 	m.Group("/user", func(r martini.Router) {
-		r.Any("/login/github", reqSignOut, oauth2.LoginRequired, user.SocialSignIn)
 		r.Any("/login", binding.BindIgnErr(auth.LogInForm{}), user.SignIn)
+		r.Any("/login/github", oauth2.LoginRequired, user.SocialSignIn)
 		r.Any("/sign_up", binding.BindIgnErr(auth.RegisterForm{}), user.SignUp)
 		r.Any("/forget_password", user.ForgotPasswd)
 		r.Any("/reset_password", user.ResetPasswd)