I signed up for the bowob site a few weeks ago. The chat was great, people on the site loved it.
I received an email saying that either I had to either allow them to put an aesthetically displeasing ad or pay them $23 a month for the chat.
The site said it was a "FREE" chat.
After today when I told the creator I had contacted an attorney after he put an ad on my site and refused to let users hide or close the ad for the duration and will make it load on EVERY PAGE that loads he changed his site to no longer say free.
I would suggest staying away from this plug in if you are an established site. mIRC and things like that are free and wont throw an ad in your face everywhere you go on the page.