I have never contacted a hubber in this way. I'm always so worried that it would come off "creepy" or "weird" and I don't want to freak anyone out. again, I worry and over analyse things way too much sometimes (just part of my charm I guess).
I haven't been contacted in this way either, since I have not enabled that option on my profile. It isn't that I'm snobby - I just am horrible at checking me emails & wouldn't want to offend someone by not responding.
There are a few hubber who write well written material, leave great feed back on my (and other hubbers I follow) hubs, responded in Q&A, and/or exchanged some debate in the forums which I wouldn't mind getting to know a little better on a place like facebook. But again, I don't want to innitiate an invitation and over step my bounds.