Difference between Push Notification and Pull Notification?

Question

DO anyone know what is the difference between "Push Notification" and "Pull Notification"?

I know "Push Notification" is C2DM, but I dont have any Idea that what is "Pull Notification"

Anyone pls help..

Answer 1

I have to publish this answer because the accepted one is terribly misleading.

• Pull notification means a client requesting a server to check if there are any updates.
• Push notification means a server notifying a client about the updates.