If you use chat programs regularly, one of the things that can be a constant annoyance is having to contantly switch windows while you're browsing the web. Chatab.com aim to offer a solution by giving you a web app that gives you multiple chat accounts alongside a web browser.
The site allows you to add multiple chat accounts like AIM, GChat, Facebook, and many more, if you happen to have that many chat acccounts, as long as you register with the site. Otherwise, you can connect any single account directly and use a guest account on Chatab.com.
The chat application works pretty well, and when you register, you'll be able to control personal information that is displayed when people view your profile from Chatab.com, as well as your nickname for IMs. The browser is small, but adequate. I had no problems surfing site to site, even off clickable links.
Chatab.com offers a variant from typical multiple chat web applications, which often leave you in the position of switching tabs or windows like any other chat application. Still, the browser is a little bit cramped, and could probably use a bit more space to be even more useful. Go take it for a test ride, and let us know how you liked Chatab.com in the comments.