That is a cool idea. I would suggest not including advertisements just yet because they are generic and probably the least appealing of all ads (besides pop-ups). Just a suggestion, though the service itself is cool.
The adbrite signup had me list a bunch of keywords, so I figured the ads would be somewhat relevant, but you're right, they do seem generic and unrelated. Maybe that's because of the low amount of traffic so far.
I've removed them for the time being.