Facebook is Adding More Features to the Like Button
Connect with Specific Users
Facebook encourages websites who people may want to connect with, such as a brand or product, to send out relevant updates to its connected users. For example, for those who have liked a specific product, send out a targeted special to them only.
Facebook recently added the ref and source parameters allowing testing and optimization for the use of the Like button on your website. This will easily allow you to do a/b tests of placement and types of the Like button.
Know Where They’re Clicking on Facebook
When using the ref parameter, you can also add a fb_source parameter to find out which type of stream it is, and where the click happened. Facebook filters the URLs to protect user privacy. It removes personal information while still exposing the anonymous source.