Hm, it seems I stand corrected, the list doesn't work like I thought it does.

However, I still don't understand what it's supposed to tell me. See for example (randomly chosen): https://github.com/peterb

According to Github his fork of "carrierwave" is his repo with "the most stars and watchers".

Well, it has 1 star. And I apparently can't see the number of watchers.

Neither can I see the list of commits/issues/pulls that peterb made to this repo, or which of his commits were merged (if any). Github shows me absolutely nothing that would let me gauge the quality or quantity of his contribution(s). Perhaps he's on the core-team of carrierwave, or he just corrected a typo in the README at some point - I'm none the wiser.

The key mistake here is to rank the contributions by the popularity of the project that was contributed to. Fix a typo in the README of Rails and that will likely remain your "top contribution" forever [unless I'm still misunderstanding how the list works]. It's the definition of vanity-stats; figures that can make you feel good but are ultimately misleading.

PS: If peterb is reading here: Sorry for using you as an example, I just clicked a random name on the list of rails-forks.