Anybody know which projects release their results to the public domain? Are there any that don't?

Both BURP and RenderFarm has their animations available.
You can download MBs or even GBs of prime-numbers from PrimeGrid IIRC.
You can view computed played games of Chess960
..

Some project accept (or plan) submiting users task to be computed on their project (BURP, RenderFarm, Leiden).

Some projects like CPDN (and SAP), Einstein, Rosetta/Ralph published their results in scientific papers and they eventually get available on website. Or are about do so when results are available, peervied and published (RCN for example).

(what has SETI to offer in this area - despite of enourmous effort of participants - is hard to answer for me)

You can see that there are outputs available to participants and general public.

Hope it has answered you question somehow...and that I have understood it correctly.

Yep, that's the info I was looking for. I also found out that Nano-Hive will release all of their results and QMC will publish theirs.

I just don't want to compute for a project that's doing it for a profit but looking on a lot of their websites it's tough to figure out if they're going to publish their results, release it to the public domain or try to patent it.

Ask on their forums for that information, like they did here