Now that Facebook is fully supporting custom iFrame tabs and phasing out FBML and the Static FBML support, many page admins are wondering how best to add functionality to their iFrame tabs.
For example, how do you add popular FBML tags that facilitated interaction on Facebook, such as Reveal/Fan-Gating, Multi-Friend Invite, Share button, Like button and Comments.
Facebook Social Plugins to the Rescue!
Fortunately, a subset of the XFBML tags (a.k.a. Social Plugins)