I use github stars in a similar fashion to you - just recognition. It's also kind of like Hansel and Gretel's breadcrumbs - it's just a note to say 'I was here' to myself on the github repo.

I'm using pinboard stars differently though - it actively means that I've come back to that resource, it would be as if you could give a gold star to a github repo if you actually downloaded the code. I guess you could fork it, but I only fork something if I want to make changes rather than just use it.