The Anti-Facebook

Facebook is all about friendship and liking things, right? Wrong. One app developer has launched a service enabling users of the social network site to list their enemies, be they people or companies.
Named EnemyGraph, the application is available for free on the site, and even includes an "archenemy" option, for those people or things people truly dislike.
Even the technology behind the app runs contrary to that of Facebook. It employs something called "dissonance" queries to flag disagreements between friends, a stark contrast to the affinity-based searches used by the social network to highlight shared interests.

Some 3.2 million Facebook users have already signed up to a group calling on the site to offer a "dislike" button in addition to its current "like" option.