you can't send messages among different apps directly. But you can write your own protocol and communicate through url fetch / xmpp etc.
With regards to user account, an easy way it to use google account directly. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-appengine/-/reaT1zkoo90J. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
