Sometimes I wonder how Amazon.com has any success at all with their product recommendation engine. It makes sense when after I buy gifts for my niece and nephew it starts recommending toys, and the constant recommendations for interaction design books since I buy quite a few, but what about the time it started recommending scuba gear? or engagement rings? (that was well before the marriage ruling, back when I still didn't have the right to marry, or a boyfriend for that matter)

I'd like to see it figure out that having only ever bought games for Nintendo Wii, I might not be interested in (or able to play at all) PlayStation and X-Box games.

Checking on something this morning, I was pretty sure it knew I already read Dava Sobel's Longatude. Clicking to see why it was recommended, I found out it was because I already owned it. While it was completely accurate in recommending a book I would like, I'd rather have it recommend something I haven't already read.