“is meant to help you keep track of some of the items you’ve recently viewed and help you find related items that might be of interest. As you browse through the store, we will bring to your attention items similar to those you are looking at. Since your browsing habits change frequently, the Page You Made changes as well, and your sessions expire after a few hours and are not stored on the Amazon.com site. This way we can offer you the most relevant purchase suggestions for your shopping sessions.”
Now Amazon tracks the products you looked at and puts them into one neat page, a sort of 0-click wish-list adapted to the current shopping session.
12/2014 update: Facebook gets into this type of automated personal content that you didn’t know you didn’t want until someone showed it down your browser.
02/27/01 update: more (insider) information.