Comment by SwellJoe

They mostly don't matter to users, because most forks fizzle out due to lack of interest, unless there's a really good reason for the fork. If the original maintainers aren't doing something weird like re-licensing under a more restrictive license or closing off development and refusing good patches from the community, it's very unlikely a fork will gain enough traction to end up on the radar of most users.

We've had a few forks of our projects over the years...most often, there's just one initial commit with a few minor changes and some big words about how cool it'll be when the community can steer the ship...and, then nothing, forever. The thing about forking a big project is that it takes a lot of time and effort to make it better, or even significantly different, from the project you're forking. "Do not fork lightly" is good advice, but mostly because it's gonna be a waste of time in most cases.