I've been using Last.fm for ~15 years now. I love to see my stats -even if I don't listen to music as much as I did when I was a teenager-. In the process of keeping my profile accurate I developed an open source tool (Open Scrobbler[1]) which ended up being used by thousands of users. Even now that last.fm is not as active as it was 10 years ago, the project is self-sufficient through its Patreon. I've also used it as talking point on job interviews as well. I'm very grateful for all the experiences and people I met thanks to last.fm!
[1]: https://openscrobbler.com/