The Open Graph Initiative:A primary reason that Facebook expands is the network effect: more users mean more value. In April 2010, Zuckerberg announced Facebook’s new initiative called Open Graph.The goal was to connect all the different relationships that exist on the Internet by linking web sites to Facebook. Programmers at external web sites were encouraged to include a Facebook “Like” button on their web sites.That way,when Facebook members visit the web site,they can click the Like button,and their relationship with that web site will be reflected back on their Facebook page for friends to see.