These websites provide social networks with a focus on business. By far the most popular business social network is LinkedIn with over 8.5 million registered members. While the others have large communities of business people, those networking with LinkedIn usually report the most activity.

A social network of over 9 million business people where individuals create a professional profile and network with others by making connections. After creating a free account the first step is to setup your profile and then use the search to see what contacts of yours are already a part of LinkedIn. You can then ask them to connect with you along with anyone else you know who is not already part of the network. As people connect with you, they become a "first-degree" connection while their connections become "second-degree" connections.

By creating connections you establish a network of contacts. You can use this network of contacts to find people and business opportunities along with requesting or providing recommmendations. As you receive recommendations you can be listed within the service directory. Additionally, LinkedIn provides an Answers area where you can ask questions or contribute by sharing your expertise. As you make connections, earn or provide recommendations, and answer questions this activity becomes part of your profile. You may specify which areas of your profile are published and available based on a person's connection status with you.

Build your own social network in minutes. Similar to the viral thing and all you have to do is join and email your friends ect to join then they do the same and so on. It is free to join and I have met some nice people there and had some hits on my website from it too.