Unclear, I think. I tend to use GitHub stars as bookmarks, which implies interest but not necessarily hearty approval.

I don't think you can generalize here; it's like Twitter, where some people use Likes to remember all-time favourites and some people use them as an "I've read this" checkbox.

Besides the thing sibling commenters mentioned about GitHub Stars acting like bookmarks, I also feel that GitHub Stars are more intended to be used to indicate interest in the source code itself—which is a bit different from indicating interest in the product you get by compiling said source code.

I might Star e.g. Postgres (yeah, I know, not their official repo) because someone told me that it's an example of good, elegant code, and I would like to study it. But that doesn't mean that I'm a Postgres user, let alone an adoring fan. I'm starring the code.