I recently joined twitter, and as a friend of mine has said, it works very well for what it was intended for; telling your buddies what bar is hopping tonight.
Other than that, in 140 chars about all it's good for is pointing your friends to websites or photos. It is good for that. But it doesn't really do anything that LJ doesn't do, and the 140 char limit means it's pretty useless for saying anything useful on its own.
Heck, I can't even say "hello" in 140 chars. I mainly joined Twitter so that I could set my location to Tehran and throw some sand in the gears of the Iranian security forces that were trying to shut down political twittering.
You're his wife, hon. It's expected that you've been filtering his verbiage for years. You're just listening to those danger signs, like you do with the kids and those menacing silences, so that you can preemptively prevent too much in the way of doom.
Just let him play with his dollies, and he'll be fine.
You may also want to let him know that you can create friend groups on Facebook. It's a nifty feature that isn't very noticeable with the new layout. When you log in, there are a bunch of links on the left like "Photos" and "News Feed", and underneath that is a link that says "+Create" -- that's the magic button to start placing your friends and acquaintances into neat categories.