Every time you ask the user to accept push notifications you get a token that's unique to the app instance on the device. You then use this token to send a push notification either through APNS or GCM.
In essence, a registration token represents a user. Since you hold the tokens on your server, you need to implement the logic that decides who should receive a notification on the server.
the Telerik team
Don't miss the Icenium May Release Keynote - sign up now!
Share feedback and vote for features on our Feedback Portal.