Social Networking Guide

Hello there

I am after a guide which gives an overview of all social networks that are used today. Such as Linked In, Twitter, Facebook etc.

On each social network I need the following information written:
- What is the target audience?
- Who uses this network and for what purpose?
- A brief introduction to this network
- Benefits to business for using this network?
- The URL to sign up for this network
- Number of members the network appears to have

I require this in MS word format with focus on the content rather than the design. I would expect to get around 30 different social networks with this project.

Apologies the budget is tight and not flexible due to being a start-up.

Thanks
Andrew