It is hard to ignore LinkedIn and its 10 million-plus users. It seems like a day doesn’t pass without an old college classmate, former coworker or late night business school study group partner reconnecting via LinkedIn.

http://www.linkedin.com/static?key=press_releases_041107

What I like about LinkedIn:

1. Easy access to vCards for the most important nodes of my professional network. I can forget about Outlook Contacts when I have a virtual repository that is always up-to-date. (What happened to Plaxo?)
2. “Who has viewed your profile” – Despite the uncertainty of who exactly viewed my profile, I am always curious about why the random person from random company is “checking me out”. Many times it is the precursor to an invitation from that long lost friend or colleague.
3. “People you may know” – I marvel at the their power to predict people who I already may know. They range from a roommate of my Marketing Analyst to a candidate I interviewed six months ago. In the end, I can see how the more nodes in the network make it a more powerful tool. This is also a creative way to get me to link with additional people.

LinkedIn proves social media can work in the B2B world. If history repeats itself, we’ll see many more innovative sites like LinkedIn that capture the attention of millions of career-oriented B2B types.

Any site that you like?