[XiZa]

The advantage is that users without javascript simply won't see the channel. The channel is hidden by default (style=display:none) and then shown via javascript.

Or does the channel work without javascript as well? I tested it and it just showed a "loading..." message but I forgot to check if I could post stuff on it. Maybe there should be a fallback with iframe that refreshes every x seconds instead of ajax. Ofcourse that won't be able to use the new functionality you are hopefully going to incorporate (json ) but I think only a small part of the usrs will have javascript disabled. Maybe you should also do a check to see if ajax is enabled (and put that value in a cookie so as not to check on every page) and if not use the iframe fallback.

Btw, this message:

"Error : you can't send a private chat to this user as he doesn't have the necessary permissions to use this feature.
"

should be "he/she", not just "he"