What networking/marketing sites work for you

Just wanted to ask what networking/marketing sites to you find you get the most traffic to your respective sites. I personally find my number one is Linkedin at over 300 plus referrals a day to my site. My next is BT Business Tradespace I only joined it some 9 months ago but have found it to be my no1 source of new business to my site. What I like about the site is the things you can do on it, post up to ten videos,50 photos, blog,all links to my site. But Most importantly you get to chat to like minded prople just starting out, which is great on drawing on other peoples expierences. You never get accused of posting spam that actively encourage you to talk about and post things about your business. Mst of the networking sites i go on you post anything about your business your accused of spamming. They have over 300,000 members already and backed by the BT brand.
So visitors referrals to my site
it has to be linkedin just but for the interaction and actuall sales it has to go to BT TRADESPACE hands down. So tell me your top networking sites be interested to know your thoughts, all my stats come from google anaylitics.

All the best
Michael