Having a site where stats are populated once a day, or once an hour is nice, but what if you want to tell other people that your site is doing well? What can PHP do for you if you want to keep track of things like "current visitors" or "page execution time"? Well, according to this article from phpFreaks.com, there's quite a bit.

Build a People Online Counter with PHP and MySQL helps you out with code and database layouts for the various stats that they have on their site, like those mentioned above and others, including "members online", "total hits", and "total memebers". Of course, the "current people online" stats are just approximate, since HTTP is a "stateless" technology. You can't really tell when people come and go, just when they interact with your pages.

This article has some good info in it, but people with a login system already in place might have a little trouble integrating it with their system.

Thanks to Ewald for the link...