We use a site called Yammer as our social network in Best Companies. It acts as a place for staff members to share thoughts and ideas, see what's going on and get involved in things that interest them.
It includes work related stuff, some non-work related stuff that people might be interested in, early looks at products that are being developed and a whole host of other bits and bobs that give you the inside scoop on what's going on in the company.
To access Yammer, you can simply goto www.yammer.com in your web browser and log in with your Best Companies email address. It has it's own password for now (although we're looking to tie this up with our website in the near future) so the first time you visit the site you will be asked to set up an account.
Here's a quick guide to Yammer which may be worth checking out before visiting the site;