It identifies code markers such as TODO, FIXME, HACK, XXX, etc (soon to be customizable) and surfaces them as cards in a web UI. There's a free and open-source CLI as well.
The web app is free for public repos and $3/month for private ones. I'm looking to add organization/team-based pricing soon too.
A feature that I'm hoping will have an impact will be a "TODO reminder" email that will email you within a configurable amount of time after a TODO is added to a codebase.
Right now it's just me working on it outside of the day job, I'm hoping I can turn it into a useful tool for developers!