Our company gives them money but the main thing is that we have a lot of small private projects that are more like prototypes and will never see the light of day. We are not permitted to open source them and probably wouldn't if we could because they'd be worthless to everyone but us. The pricing plans for additional private repos is pretty steep with github so we had to pay for a crappy repository hosting service to dump all of our second tier projects. GitLab would be pretty neat to allow us to store our second rate stuff on our own servers and the stuff we use every day on github.
Why not use bitbucket.org instead if you have a bunch of small private repositories? They allow for unlimited private repositories, and it has been working quite well for me.
So they re-opened that offer? When they closed it I had to endure about six dire e-mails when all I wanted to say was screw you, I've already re-hosted my stuff.