Please read this answer in its entirety before reacting.
If your goal with this approach is to have relatively hassle free marketing for your services, your approach is untenable. You're going to deal with these headaches no matter what kind of license you have.
The download sites aren't going to read your license for the most part. They count on your apathy in enforcing your copyright , not just your license. That being said, here's some things to do:
- Report the links. Contact the ad networks themselves that appear on these pages (i.e. Google) and report the copyright violation. Google takes these very seriously, so do most other (reputable) ad networks.
- Talk with an IP attorney, really look into the cost of getting your own license drafted. Its as cheap as a few hundred bucks. The same attorney can then help you to enforce it, if needed.
- Have your program check for periodic updates, which takes people to a download link on your site should one be available. That helps put what the download sites are doing to work for you rather than against you.
Big names have this issue too, just not to the extent that you have it. They employ people to look for this and send take down letters on the spot. Again, looking at your business model, you simply do not have time for that.
Really, really, really try to find a way to make this a positive thing, complaining to the ad networks as a last resort. Try to find more ways to plug your site in the app itself without annoying users.