I've thought about that from time to time - it's an excellent idea.
Right now, the easiest thing is, if (and this can be a big if) you've got a .Mac account, you can publish them there. I can start a web page with a list of users who have stuff published, and people can add it to their .Mac shared browser list. (I can set up something for the next release that would include being able to automatically update this with a list of accounts that people submit to me).
Of course, if you don't have a .Mac account, it becomes trickier. I've thought of having a similar shared images run from gandreas.com but I've yet to get around to properly set up all the little server details to make it easy.
Definitely a good idea - at the very least, I'd recommend getting an account with deviantart.com and upload rendered images there (though you can't share the quadd files easily). You can see mine at http://gandreas.deviantart.com
. deviantart, unlike flickr, encourages things like computer based art (I had originally looked into adding support for uploading to flickr, but they're focused on photos - if deviantart ever provides a client api for uploading images, I'll set up some sort of post-render action for it).
If I get a couple more people with online quadrium based galleries I'll add a links page as a first step...