As someone who screens candidates where I work, I often check if a particularly worthwhile candidate is registered on LinkedIn in part to cross check details th

As someone who screens candidates where I work, I often check if a particularly worthwhile candidate is registered on LinkedIn in part to cross check details they provide on their resume and occasionally add them as a "connection". I think this is the limit of acceptable behavior, in part because LinkedIn's focus is professional. The only exception I can think of would be a job in which maintaining a highly public Facebook or MySpace page was itself an essential function.