But .. is it really worth diluting the brand, and diverting the team's attention? I have seen personal articles on a username.github.com blog which have nothing to do with code. Someone seeing the site via one of these avenues for the first time would come away with the impression github is a free blog provider. And, amongst other things, they are!
And what happens when people start, saying, hosting large media files? It might not have happened yet but it will. Then one of them gets slashdotted, the site slows to a crawl, and the team's running around putting out fires caused by some free service which doesn't have anything to do with version control, just "adds value" to having an account on that site.
Well, I guess they've thought all this through and decided it's in their interests. I was just surprised, is all.