Facebook plugins Useful for Search Engine Optimization
Facebook's "social plugin", as they called their Like button, can be integrated into a website, along with Activity and Recommendation feeds. The Like button enables users to bookmark specific sites which are then viewable by their friends on the user's profile page.
Their Open Graph and Graph API are are plugins for developers which enable businesses to integrate Facebook features into their websites. SEO experts have pointed out that features such as the Like button can certainly have effects on SEO, and can easily be integrated to search specific algorithms.