Facebook = Granfalloon

Earlier last year, Emily Yoffe wrote a humorous column for Slate titled Fiftysomething, Facebooking, and Fabulous! with the sub-heading, "Last week I had zero friends on Facebook. Now I have 775."
Although it has some "old-fart-discovers-new-tech" content, it also has many witty observations and anecdotes about Facebook, and about friendships.
I learned a new word from the column - granfalloon, which Yoffe used in reference to having too many Facebook friends and being in Facebook groups/networks. Other writers have also used the word to describe the sometimes-superfluous networks formed by users on social networking sites like MySpace and LinkedIn.

From Wikipedia:
A granfalloon is defined as an imagined community, that is, a group of people who outwardly choose or claim to have a shared identity or purpose, but whose mutual association is actually meaningless. The most common granfalloons are associations and societies based on a shared but ultimately fabricated premise.

What a wonderful word, and could there be a more fitting description of Facebook?

It is interesting to note that granfalloon isn't even a new word. It was coined in 1963 by Kurt Vonnegut (RIP), in his novel Cat's Cradle.

Full disclosure: I've recently updated the Wikipedia entry on granfalloon; I added the part about social networking sites.