Words are inadequate

I know of a good dozen other sites based on LJ's codebase, but LJ's the only one with tens of millions of users.

I do share mostly the same links on LJ and FB--and while I have a Twitter account, I almost never use it--but if I have more to say, that stays on LJ. I don't expect that anything I post on FB is necessarily read by the bulk of people who have access to it; on LJ, I have a reasonable expectation that most of my LJfriends will see it. (I do personally know 90+% of my FB friends, but it's still a shallower connection.)