Why do people take LinkedIn so seriously? I will accept stranger's requests if I think they could provide some kind of useful service to me now or in the future.

I'm not maintaining a list of important relationships on it. It's a rolodex to me and a business card can and should be added to it whether or not we've done business already.

This idea of carefully pruning your connections seems quite popular. To those that do it, what's the upside? (The upside to letting almost everybody connect is that, if in 5 years I need to contact somebody or they need me it might be a little easier for us to get in touch.)