[shabble]

Do you need an account to be able to report issues or watch projects? Interested bystanders and responsible bug-reporting OSS citizens may account for some of that.

I wonder how many of those accounts have active repos of their own?

[Zev]

I would wonder how many of those accounts have pushed to a repo recently, not just their own (in cases where people work for a company/on a project that has a GitHub organization).

[andrewl-hn]

Yep, that's a valid point. I got my account for more than a year but I use it to report issues and for Gists only.