I'll chip my two cents worth in too...
I have to agree with trabis fully here.
I did not spend the last three years of
my life building a website just to promote
a social networking site that has nothing
to do with anything even remotely
related to things I am interested in.
I've tried a few of them in the past and
quite frankly they just don't work for me.
Some folks might want to casually insult
them as being pieces of crap but as webmasters
all of us know how much work it is to build
and maintain any website.
(Even if most social network's "content"
is from users telling the world at large
they are eating a Twinkie ATM. lol)