etckeeper was a sleeper success for me. I created it, wrote one blog post about it, installed it on all my computers, and mostly forgot about it, except when I needed to look something up in the git history of /etc it helpfully maintains. It's a minor project.
Then I started getting patches porting it to many other version control systems, and other linux distributions, and fixing problems, and adding features. Mountains and mountains of patches over time.
And then I started hearing about distributions that install it by default. (Though Debian for some reason never did so I keep having to install it everywhere by hand.)
Writing this blog post, I noticed etckeeper had accumulated enough patches from other people to warrant a new release. That happens pretty regularly.
So it's still a minor project as far as I'm concerned, but quite a few people seem to be finding it useful. So it goes with free software.