There are more than 75 million professionals registered on Linked In. Bebo: In the United Kingdom, Bebo is the second best social network.
Bebo allows users to create social networking profiles for free.
You can build your network of contacts, and invite others to receive your Tweets, and can follow other members' posts.
Twitter makes it easy to opt into or out of networks.
Using you can: o Browse and join networks, which are organized into four categories: regions, colleges, workplaces and high schools.