I would think merged pull-request (aka community patches that doesn't suck) would be a better indicator on gh - at least for open source project. Fixed issues a close second.
Don't know how common it is but I for one use the starring function to tag projects that I'm not using! This is so I've got a note of it to look at later.
For projects I'm actively using, I'll either have a fork, or just a clone of the repo locally.
Cachet (https://github.com/cachethq/cachet) has 2.6k stars but I know that the amount of installs is actually far higher.