Soooo not what facebook is. The "competing obsessively to fill your friends list" thing sounds like something Fox News would say about sites like that.
The biggest irony of this statement is that Rupert Murdoch has owned MySpace for several years now. So I doubt whether Fox News would say anything that might seriously hurt the business interests of a service that shares its parent company.
In Last.FM's defense, I would say that it's not *primarily* about gathering playlists, and showing off what you listen to (which can be done using just about any other social networking sites).
What makes it distinct, for me, is the feature that measures your own music consumption, versus others' (both strangers' AND contacts'), to come up with lists of potential music recommendations (based on one's recent listening habits, AND overall patterns, from the time they sign up).
Plus, there's the prospect of observing the listening habits of people whose music tastes are similar to my own. (Which is part of the reason my own contact list has swelled so much, in the 2 1/2 years i've been a member.)
The fact that 80% of these folks with similar music tastes happen to be cute bespectacled indie rock girls with awesome hair is *totally* a fringe benefit :twisted:
But seriously now, I've "discovered" loads of bands and performers through Last.FM whom I might not have stumbled upon otherwise, because of the sheer breadth of possibilities alone (compared to relying on, say, music blogs or forums/message boards dedicated to particular type/genre of music to find out about new bands).