If it's an AJAX shoutbox, it depends on which one it is. One of them that I know of is known to open up several instances of PHP instances. Like with my home web server which is still being used, one of the small forums I host for a friend, the admin had installed an AJAX shoutbox. Well, their members started to use it, and when I was working on the server and Google decided to hit the site, I saw one instance of PHP start up for Google and it worked fine, while a few seconds later, I saw 10 instances of PHP all open up at once just because of the shoutbox mod and because of Google just loading a single page, so 11x1 user is a lot for one page call, especially the fact that it has to talk to MySQL and run 20+ queries just for one thing as well. Geez.