For SEO purposes you needn’t use ‘humorous’ in every question - most people don’t search for humor or humorous I wouldn’t think, but would likely more likely be looking for funny, joke, comedy, etc. That just helps people find your site when that is what they are looking for.
Personally, I use twitter for most of my comedy now - there are some very funny folks, so daily I can open my twitter and get all the laughs I care for.
Also, it isn’t immediately clear to me by looking at the site that this is an open participation welcome type thing. I read, I scroll, I move on - it doesn’t scream “you’ve got something funnier, say something!” And the lack of comments further remove the chance to participate.
The blank avatars are annoying and make the site look dull and boring and lifeless. Either remove them entirely or have it so a person gets some icon, even if randomly assigned on signup, and has a list of icons to pick from if they don’t want to load in their own. Would add color and some personality to the site.
The idea of using openID would be cool too, just because I wouldn’t mind posting something funny and quick with my twitter account or facebook, but people who have something funny to say are usually also very lazy. Comics are, by nature, unmotivated and tend towards sedentary. Anything extra they need to do to participate will drive them off in droves.
With comments, perhaps some tagging fun sort of rating system (silly, LOL, LMAO, ROFL, ROFLMAO, ROFLMGDAO, ROFLMGDAOUCCHSYCDOL (roflmgdao…until the cows come home and steal your car and drive off laughing)), and things like that you’d have a reason to email people updates. “Sheila says you are hilarious, ten people think you are thtoopid - prove them wrong!”, that kind of thing - to get contributors to come back and participate more.
Also, the thing every funny person enjoys about comedy is making people laugh. If all you get is a silent little posting of your joke with no response other than perhaps +1, there is no reason to bother - what’s in it for the funny person?