Google's AdSense is a superb revenue generating opportunity for small, medium and large web sites.
Some webmasters are designing brand new sites specifically for serving AdSense text ads. (It's against the AdSense rules to design a site purely for AdSense, so you'll want to include a few affiliate links or sell your own product, too.AdSense allows you to serve text-based Google AdWords on your web site and receive a share of the pay-per-click payment. AdSense ads are similar to the AdWords ads you see on the right-hand side at Google when you do a search there.
AdSense is having a huge impact on the affiliate marketing industry. It's often much easier to generate revenue from AdSense than from an affiliate program.
Weak affiliate merchants will die faster than ever.
If you're a merchant running a lousy affiliate program, now's the time to improve it FAST.