A friend recently invited me to into his LinkedIn network, and I accepted. Since then, I have added a few more people to my connections.

You'll have to check it out yourself to get an idea of what it's for, but basically it's like Orkut for the business world. I know a couple of people who are actively using it to find a job, which is one of LinkedIn's selling points - find jobs, or as an employer, find employees.

If you check it out, and like it, either let me know your contact info, and I'll invite you, or you can sign up and invite me into your network.