It seems many people are struggling with how to classify different contacts in the social networking services you use: is your boss your "friend" on Orkut, and are your drinking buddies valid LinkedIn contacts?
To make things easy, let me introduce the beer rule:
- User needs two social networking services. I use FaceBook to keep in touch with friends, and LinkedIn with business contacts
- If you can contact somebody at any time and go for a beer: personal contact, ending up in FaceBook
- If money is involved: professional contact, ending up in LinkedIn