If you click on your "Monetize" tab , then click "AdSense for feeds" you get a link like this:
Only thing is, I don't get what it's for. Can anyone fill me in?
EDIT: Thanks to your comments, I now have the answer. Here's the best answer:
If someone subscribes to your blog via RSS it puts Adsense ads in the RSS feed itself. In others more clicks and more money. The link they give you is how your followers can subscribe to your RSS.
Credit goes to Chris. Thanks a lot. In appreciation, here's a free promotion of your blog: