You can't really advertise as such... but you could always ask for a review or advice about your AdSense placement. You need to think outside the box on this one and don't appear as if you're spamming. (But don't tell anyone I said that!)
You can advertise on DP working with Google Adwords, on each page you see Google Adsense advertisment on the top right, underneath it you see 'Put Your Advertisment Here' click that and follow instructions on that page. Good luck.
Click into "Forum Jump", Under "The digital Point". There is a topic called "Review". You could ask people how they think of your website. I'm sure lot of DP pals outthere will give you some opinion.