I have several FB friend groups, and I create one for any company I'm working for. Anyone I'm currently working with goes in there, or in the "ultra" group I've also created, where they can't see most of my wall nor post on it. Usually I'll add people when we've stopped working together, though. And not unless they request it. It's rare that I request it.
"This thread reads like a series of White House memos." — Mister Matt