facebook application tabs & realtime update question

1.i see in th开发者_JAVA技巧e developer page app config a section named "Page Tabs" , what is it for? 2. anyone has example of facebook graph "Real-time Updates" in php?

"Page Tabs" are applications which appear under their own tab heading and can be added to fan pages. At present they can only be built using FBML, but are schedled to switch to an iframe implementation this quarter.

Further info - http://www.facebook.com/notes/pop-art-inc/the-state-of-facebook-tab-applications/442661413507