Josiah turned me on to AudioScrobber, which tracks what music you play for the purpose of recommending songs as well as comparing common musical themes between members of AudioScrobber groups (for instance, Josiah started one named after his blog).
The problem is that its update application leaves some functionality to be desired. It isn't a plugin to iTunes, it runs constantly in the background instead, watching for when the Recently Played playlist is updated in iTunes. Not quite comfortable making it an auto-start application until I used it for awhile, I started it manually. Shortly thereafter, I was away from my desktop for ten days, during which time I did not synchronize my iPod (I don't synchronize it with my laptop).
Tonight I plugged it in, forgetting that I had restarted my desktop (and therefore needed to restart AudioScrobber's tool) and therefore despite the fact that I had listened to a lot of music during the evenings the past two weeks, none of it will show up on my statistics page. Since some of the stats are only produced once a week, I'll wait another week before linking to my page on the site, since the stats still aren't that useful (grumble) unlike how they would have been if the app had just been a plugin and therefore would have caught my iPod sync.