How Do You Build A Who's On Application?

One question I see a lot of is folks wanting to build a 'Who's On' function into their web sites. In its most basic form such a thing is mostly just an 'oooh cool' kind of feel-good thing that doesn't accomplish a lot. However with very little effort you can store invaluable nuggets of information.

Exactly what those valuable things are for each individual site varies, and is beyond the scope of this article. However, we'll lay down the basic framework here and you can easily add your own goodies later on your own.