I noticed that the logged-on users are shown on the forum but not on the site. Would it be possible to show them on the site as well without too much work ?

Both are completely independant actually.
The site is made by me, the forum is not
The info about who is on the forum is actually "who asked a page of the forum in the last XX minutes".
I could do the same on the site, but there are already so many things to add I'll see how easily it can be added

Thanks, I knew they were independant. Don't bother with it until you have other things done.

By the way, I will be glad to help post contributions if you tell me what to do.