diff --git a/src/Yavsc.Server/NotificationTypes.cs b/src/Yavsc.Abstract/Messaging/NotificationTypes.cs
similarity index 79%
rename from src/Yavsc.Server/NotificationTypes.cs
rename to src/Yavsc.Abstract/Messaging/NotificationTypes.cs
index 94568868..b0c82f31 100644
--- a/src/Yavsc.Server/NotificationTypes.cs
+++ b/src/Yavsc.Abstract/Messaging/NotificationTypes.cs
@@ -7,9 +7,10 @@ namespace Yavsc
         public const string UserPart = "userpart";
         public const string UserJoin = "userjoin";
         public const string PrivateMessageDenied = "deniedpv";
-
         public const string Error = "error";
-
         public const string BookQuery = "bookQuery";
+        public const string ContactRefused = "contact refused";
+        public const string ExistingUserName ="existing user name";
+
     }
 }
diff --git a/src/Yavsc.Server/ErrorMessages.cs b/src/Yavsc.Server/ErrorMessages.cs
deleted file mode 100644
index f49c3069..00000000
--- a/src/Yavsc.Server/ErrorMessages.cs
+++ /dev/null
@@ -1,6 +0,0 @@
-namespace Yavsc
-{
-    public static class ErrorMessages {
-        public const string ContactRefused = "contact refused";
-    }
-}
diff --git a/src/Yavsc/Controllers/Contracting/CommandController.cs b/src/Yavsc/Controllers/Contracting/CommandController.cs
index 6248c2bc..b4224132 100644
--- a/src/Yavsc/Controllers/Contracting/CommandController.cs
+++ b/src/Yavsc/Controllers/Contracting/CommandController.cs
@@ -191,7 +191,7 @@ namespace Yavsc.Controllers
                     nrep = new MessageWithPayloadResponse { failure=1, results = new MessageWithPayloadResponse.Result[] {
                         new MessageWithPayloadResponse.Result 
                         { 
-                            error=ErrorMessages.ContactRefused, 
+                            error=NotificationTypes.ContactRefused, 
                             registration_id= pro.PerformerId 
                         }
                     } };
diff --git a/src/Yavsc/Hubs/.ChatHub.cs.swp b/src/Yavsc/Hubs/.ChatHub.cs.swp
new file mode 100644
index 00000000..81ceb92a
Binary files /dev/null and b/src/Yavsc/Hubs/.ChatHub.cs.swp differ
diff --git a/src/Yavsc/Hubs/ChatHub.cs b/src/Yavsc/Hubs/ChatHub.cs
index 2bf31021..4eb2b229 100644
--- a/src/Yavsc/Hubs/ChatHub.cs
+++ b/src/Yavsc/Hubs/ChatHub.cs
@@ -189,6 +189,17 @@ namespace Yavsc
             public string Topic;
         }
 
+        public void Nick(string nickName)
+        {
+            var candidate =  "?"+nickName;
+            if (ChatUserNames.Any(u=> u.Value == candidate ))
+            {
+                Clients.Caller.notify(NotificationTypes.ExistingUserName, "name already used:"+nickName);
+                return ;
+            }
+            ChatUserNames[ Context.ConnectionId ] = "?"+nickName;
+        }
+
         public void JoinAsync(string roomName)
         {
           var info = Join(roomName);