I was at Amazon.com getting some stuff and clicked on "Richard's Store" tab which of course led me to their "Recommended For You" page. Suddenly I was lost in collaborative filtering hell. All I could find was stuff that I already had or that I had already considered and rejected. I could not find anything that interested me in the slighest and the further I looked the worse it got. Have you ever been lost in a maze of twisty little web pages with no idea of how to get out? The only cure was to exit completely and come back in through the front door.
I will never visit my personal store again!