Track a certain user's posting habits?

[Wired1]

For accounting purposes, I need to count how many posts 1 user of our staff does each week. Breaking it down statistically (hourly, daily), would be cool, but not completely necessary. I was trying to make one based off of the stat page, but well, it didn't work :)

It's only this one userid that needs to be tracked, so it can be a static variable.

Any suggestions / help?