Social Media for Professionals

A reader commented on Wednesday's post about how I've been using social media, and he included a link to a business oriented website that I've never heard of: http://biznik.com.  I decided to sign up for it when I read the following on their website:

• Their tagline made me laugh: "biznik: business networking that doesn't suck."

• Their membership terms and conditions includes this statement:  "I certify no aspect of my business or the business I represent involves recruiting other people to sell third-party products or services so that I can earn a percentage of their sales (including hosting parties)."

I'm new to it, so I don't have much of an evaluation to share just yet.  I'll gladly reference it again in a future blog post if I think it's a "must-use" networking site for business professionals.

Do you use any professional networking/business oriented websites?  If so please share in the comments!