“Every email service has its own spam-fighting system, and every web company that reaches the scale of SoundCloud has to solve this problem one way or another,” SoundCloud developer evangelist Erik Michaels-Ober told me. “What we’re trying to do by open-sourcing it is to make it free and customizable so that everyone can use it to solve this problem for once and for all, so companies don’t have to build their own.”
The name “Sketchy” points to the fact that this isn’t just about spammy comments, as Michaels-Ober explained: “If you do anything over a certain threshold, it turns into spam. If you’re following people at a really high threshold, that can be spam. I’’s just general sketchy behavior.”