I went to Amazon.com this morning. Last week, I was doing a bit of research into some search engine results display stuff, and spent some time on A9. This morning I was greeted with this message:

Robert Occhialini, since you've been using A9.com recently, virtually everything at Amazon.com is automatically an additional ?/2% (1.57%) off for you. Collecting this discount is zero effort on your part. It will be applied automatically at checkout (it will happen whether you use the shopping cart or our 1-Click Shopping). You don't need to do anything to get this discount except keep using A9.com as your regular search engine.

Bribery will get you everywhere.