Gmail’s spam filter is pretty good. I get roughly one or two false positives a year. However, I think spam notification in Gmail should be redesigned. Currently, when new spam arrives, the folder link turns bold and displays a mail count. This grabs my attention.
Note: This script has been updated. You are free, of course, to use any version.
Update 11/6/2007: In updating WordPress I have apparently borked the display of the code. It is in such disrepair that I can’t remember how to put it back together. Given that this is outdated code (and now broken) and given that I have no intention of rewriting it in its original state, I don’t recommend using it.
I wrote this in 2002. I think this was the first time I used JavaScript to solve a real problem. It works well and it’s still in use on a few web sites, including HealthLinks, the site I currently work on at UW. I plan to refactor and publish an updated version soon. For now, feel free to try it out.