But it's more useful to the ecosystem as an unmaintained code dump than being kept closed. If there's interest, someone will pick it up partially or fork it. In the worst unmaintained, unused case, it's still potentially valuable for code archiving/history purposes.

I have to disagree as well. Years ago I open-sourced a little utility on GitHub and stuck the GPL on it. I had to stop working on it and soon forgot all about it. I checked on it recently and discovered that it was forked by PhoneGap and is now a critical dependency of their product. I don't recall doing anything to promote it.

Depends on the project. I've seen the argument from game developers (e.g. dwarf fortress) that open sourcing the game takes a lot of effort. I wholeheartedly disagree. You flip the switch, make sure there's an appropriate license, and the community can do whatever they like with it, and if it's well-known enough, they will. Native source ports for example. Which just happen to be the biggest reason I want the source to games.

I don't know how much clean-up id did on doom's source before releasing it, but my understanding is that they didn't do that much. And I wouldn't be playing Doom today if it weren't for that source dump.

I'm not playing dwarf fortress. I kinda would like to, though.

Not in my experience. I've pulled some very useful things out of tiny projects on GitHub, most recently a friend and I fixed several performance issues in a great voip.ms SMS client for android.

Tiny, obscure project but it was just what we needed, after a few fixes for our use cases.

I've found quite a few interesting and useful things in inactive zero-star github repos. As long as title and description are useful for search and it is not something that is totally done to death your project might be surprisingly easy to find.

Sure, but it may be the only one that's doing exactly X with Y in Z language, especially when you step outside of Java, .NET, and the other "enterprise" languages or working with hardware devices.