After some experience with publicizing mod_extract_forwarded as "my own" little piece of free software, I decided that every free software project no matter how big or how small should have a mailing list. I decided this after someone sent me some mail and we collaborated on a few pretty important bug fixes. That's when I realized, I knew other people had downloaded the module but I didn't know who or if they were using it. If they were, they really needed these fixes but I had no vector of communication other than Freshmeat.
The natural impulse might be to think that smaller programs don't merit the overhead of a mailing list, but each project should generate an amount of mail proportional to its complexity and popularity so it all works out. Conversely you should be on the mailing list for every piece of free software you use even occasionally, and the amount of mail received per list will naturally balance out. No project list is too small to subscribe to, in fact it's the big ones that are going to flood you with mail. To put it another way, it doesn't matter how many lists you're on, just how much mail they each generate.
So to make the point here, I made a mailing list for xload-snmp when I first put it up. The list stayed empty even though I got some downloads on the software. But after a few months, someone out of the blue sent mail to the list saying "hey it no workie for me." Because of that conversation I spent a couple days on the code adding a few more things really needed to make it useful for more than just Unix load monitoring. So now I feel that my mailing list philosophy has been validated.
I was also surprised by the substantial gains in functionality I got from just a few lines of code. I also understand now why everyone hates Xt. I thought X resources were hairy as an administrator, the API on the programming side is, if anything, worse.