General Social Networking Sites

1. LinkedIn - By most accounts, LinkedIn is the most popular social networking site for businesses and professionals. It's an all-purpose social network site, one that covers just about every industry.

2. FastPitchNetworking - Fast Pitch Networking is another large social network for professionals. The service has both free and paid options for users. Users who sign up for the paid service get a range of marketing and promotional features.

3. Facebook - Unlike Fast Pitch and LinkedIn, Facebook isn't primarily a business and professional site. But as the most popular social network service in the world, it's crucial for businesses and professonals to have a presence on Facebook.

4. Xing - An upstart compared to LinkedIn and Fast Pitch, XIng offers a range of features that make it attractive for business networking.

Top 4 General Social Networking Sites

1. MySpace - Although not as popular as Facebook, MySpace still boasts over 100 million users.

2. Bebo - Now owned by AOL, Bebo offers integrated instant messaging with the popular AIM service.

3. Friendster - One of the first social networks, Friendster saw a precipitious decline in recent years. But the service is still extremely popular in Asia. Joining Friendster is a great idea for anyone who does a lot of business in Asia or has lots of friends and family there.

4. Orkut - Orkut is Google's social network. While not nearly as popular as Facebook, the services seems to be constantly revising its features and services. It's still one of the most visited Websites in Brazil.