Actually, you do not need to hook it up to twitter. You can simply use, as is, and only add those who are real life friends. If you have a lot of pals and are all very active, it can be nice to see who is where.
"Oh, look, John and Kim stopped at Light House Inn for a glass of wine! Let's pop in quick before the show and say hi!"
That sort of thing.
Hooking it to twitter, broadcasting it to god knows who, can definitely be iffy. Keeping it useful amongst friends is kind of neat, though.