It's quantified BTW if you're interested in traffic/users etc

http://www.quantcast.com/mibbit.com

These things are all relative of course, so it's big compared to lots of websites, small compared to the others :/

I'm curious here, too. I didn't dig in too deeply, but I see exactly 1 ad unit at the top of the home page, no premium features for sale, etc.

I'd be interested in stats on ad units and CTR (which I've always heard is really low on communication apps).

edit: Would also be interested in definition of profitability... Covering hardware/software costs? Covering costs PLUS able to eat ramen? Covering costs plus paying yourself a market salary?

Most of the advertising comes from contextual advertising once in the chat. Also with the widget that other websites use.

The advertising revenue isn't massive yet, ($4 figures/month), but it's something to build on.

There's also obviously people willing to pay for chat/communication - campfire, liveperson type services.