LinkedIn

Social Media Platform 

LinkedIn is a network of experienced professionals from around the world, representing 170 industries and 200 countries.

Mainly used for professional networking, you can find, be introduced to, and join groups of qualified professionals that you need to work with to accomplish your goals.

As of Fall 2009, it had more than 45 million registered users, spanning 170 industries. Many consider it more of a networking than a social media site.