diff --git a/appengine/src/com/google/android/chrometophone/server/DeviceInfo.java b/appengine/src/com/google/android/chrometophone/server/DeviceInfo.java
index f8abe3e..1b97714 100644
--- a/appengine/src/com/google/android/chrometophone/server/DeviceInfo.java
+++ b/appengine/src/com/google/android/chrometophone/server/DeviceInfo.java
@@ -31,12 +31,23 @@ public class DeviceInfo {
 
     @Persistent
     private String deviceRegistrationID;
+    
+    @Persistent 
+    private boolean debug;
 
     public DeviceInfo(Key key, String deviceRegistrationID) {
         this.key = key;
         this.deviceRegistrationID = deviceRegistrationID;
     }
 
+    public boolean getDebug() {
+        return debug;
+    }
+
+    public void setDebug(boolean debug) {
+        this.debug = debug;
+    }
+
     public Key getKey() {
         return key;
     }
diff --git a/appengine/src/com/google/android/chrometophone/server/RegisterServlet.java b/appengine/src/com/google/android/chrometophone/server/RegisterServlet.java
index b58e0d7..5491368 100644
--- a/appengine/src/com/google/android/chrometophone/server/RegisterServlet.java
+++ b/appengine/src/com/google/android/chrometophone/server/RegisterServlet.java
@@ -27,6 +27,8 @@ import javax.servlet.http.HttpServletResponse;
 import com.google.android.c2dm.server.C2DMessaging;
 import com.google.appengine.api.datastore.Key;
 import com.google.appengine.api.datastore.KeyFactory;
+import com.google.appengine.api.oauth.OAuthService;
+import com.google.appengine.api.oauth.OAuthServiceFactory;
 import com.google.appengine.api.users.User;
 import com.google.appengine.api.users.UserService;
 import com.google.appengine.api.users.UserServiceFactory;
@@ -38,13 +40,50 @@ public class RegisterServlet extends HttpServlet {
     private static final String OK_STATUS = "OK";
     private static final String ERROR_STATUS = "ERROR";
 
+    /**
+     * Get the user using the UserService.
+     * 
+     * If not logged in, return an error message.
+     * 
+     * @return user, or null if not logged in. 
+     * @throws IOException 
+     */
+    static User checkUser(HttpServletRequest req, HttpServletResponse resp,
+            boolean errorIfNotLoggedIn) throws IOException {
+        // Is it OAuth ?
+        User user = null;
+        OAuthService oauthService = OAuthServiceFactory.getOAuthService();
+        try {
+            user = oauthService.getCurrentUser();
+            if (user != null) {
+                log.info("Found OAuth user " + user);
+                return user;
+            }
+        } catch (Throwable t) {
+            user = null;
+        }
+        
+        UserService userService = UserServiceFactory.getUserService();
+        user = userService.getCurrentUser();
+        if (user == null && errorIfNotLoggedIn) {
+            // TODO: redirect to OAuth/user service login, or send the URL
+            // TODO: 401 instead of 400
+            resp.setStatus(400);
+            resp.getWriter().println(ERROR_STATUS + " (Not authorized)");
+        }
+        return user;
+    }
+    
+    /**
+     * @deprecated will be removed in next rel.
+     */
     @Override
-    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
-        doGet(req, resp);
+    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        doPost(req, resp);
     }
 
     @Override
-    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
         resp.setContentType("text/plain");
 
         String deviceRegistrationID = req.getParameter("devregid");
@@ -54,9 +93,7 @@ public class RegisterServlet extends HttpServlet {
             return;
         }
 
-        // Authorize & store device info
-        UserService userService = UserServiceFactory.getUserService();
-        User user = userService.getCurrentUser();
+        User user = checkUser(req, resp, true);
         if (user != null) {
             Key key = KeyFactory.createKey(DeviceInfo.class.getSimpleName(), user.getEmail());
             DeviceInfo device = new DeviceInfo(key, deviceRegistrationID);
@@ -73,9 +110,6 @@ public class RegisterServlet extends HttpServlet {
             } finally {
                 pm.close();
             }
-        } else {
-            resp.setStatus(400);
-            resp.getWriter().println(ERROR_STATUS + " (Not authorized)");
         }
     }
 }
diff --git a/appengine/src/com/google/android/chrometophone/server/SendServlet.java b/appengine/src/com/google/android/chrometophone/server/SendServlet.java
index 6cb4581..b9b35b8 100644
--- a/appengine/src/com/google/android/chrometophone/server/SendServlet.java
+++ b/appengine/src/com/google/android/chrometophone/server/SendServlet.java
@@ -76,8 +76,7 @@ public class SendServlet extends HttpServlet {
             return;
         }
 
-        UserService userService = UserServiceFactory.getUserService();
-        User user = userService.getCurrentUser();
+        User user = RegisterServlet.checkUser(req, resp, false);
         if (user != null) {
             doSendToPhone(url, title, sel, user.getEmail(), apiVersion, resp);
         } else {
@@ -88,6 +87,7 @@ public class SendServlet extends HttpServlet {
                         URLEncoder.encode(title, "UTF-8") +
                         "&url=" + URLEncoder.encode(url, "UTF-8") +
                         "&sel=" + URLEncoder.encode(sel, "UTF-8");
+                UserService userService = UserServiceFactory.getUserService();
                 resp.sendRedirect(userService.createLoginURL(followOnURL));
             }
         }
@@ -120,10 +120,25 @@ public class SendServlet extends HttpServlet {
 
         // Send push message to phone
         C2DMessaging push = C2DMessaging.get(getServletContext());
-        if (push.sendNoRetry(deviceInfo.getDeviceRegistrationID(),
-                "" + url.hashCode(),  "url", url, "title", title,
-                "sel", sel)) {
-            log.info("Link sent to phone!");
+        boolean res = false;
+        String collapseKey = "" + url.hashCode();
+        if (deviceInfo.getDebug()) {
+            res = push.sendNoRetry(deviceInfo.getDeviceRegistrationID(),
+                    collapseKey, 
+                    "url", url, 
+                    "title", title,
+                    "sel", sel,
+                    "debug", "1");
+            
+        } else {
+            res = push.sendNoRetry(deviceInfo.getDeviceRegistrationID(),
+                    collapseKey, 
+                    "url", url, 
+                    "title", title,
+                    "sel", sel);
+        }
+        if (res) {
+            log.info("Link sent to phone! collapse_key:" + collapseKey);
             resp.getWriter().println(OK_STATUS);
             return true;
         } else {
diff --git a/appengine/src/com/google/android/chrometophone/server/UnregisterServlet.java b/appengine/src/com/google/android/chrometophone/server/UnregisterServlet.java
index 07da2bb..39b7907 100644
--- a/appengine/src/com/google/android/chrometophone/server/UnregisterServlet.java
+++ b/appengine/src/com/google/android/chrometophone/server/UnregisterServlet.java
@@ -39,8 +39,16 @@ public class UnregisterServlet extends HttpServlet {
     private static final String OK_STATUS = "OK";
     private static final String ERROR_STATUS = "ERROR";
 
+    /**
+     * @deprecated Will be removed in next rel cycle.
+     */
     @Override
     public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        doPost(req, resp);
+    }
+    
+    @Override
+    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
         resp.setContentType("text/plain");
 
         String deviceRegistrationID = req.getParameter("devregid");