Hacker News Reader

They’re a decent measure of the reputation and stability of a project. I also use the stars to bookmark my projects for later.

The developer identities that link developer activity across all projects, the network of forks.

forks, pull requests and review comments

Not much of a network effect, there. You go where the code base you want to participate in is.

It's harder to find contributors for a project that is not hosted on GitHub.