I've been playing with this pretty bonkers Java app called Firefly that allows you to see and chat to people on the same web page as you.
It's pretty flaky at the moment. The apps homepage is full of baffled messages from passers by which doesn't help much, but as a simple social tool I can see this being a great way to open up other channels of conversation within one environment.
Its a good example of how widgets and applications are changing the nature of how we interact within browsers. There's a great article on this and other next generation "post browser apps" on ReadWriteWeb .











