I let Amazon.com send me notices every once in a while, just in case something interesting pops up. This qualifies, though not in the way I expected:

Based on your recent purchases, we thought you might like to know that you can save up to 65% on summer favorites in men’s, women’s, children’s, and shoes.

The thing is, I’ve never bought clothing from Amazon! Books, CDs, the occasional DVD, some computer software. But no clothing, though they’ve tried to convince me. T-shirts aside, I prefer to be able to try something on before I buy it.

Assuming they actually are using their recommendations system, I think they must have just checked the clothing category for the mailing, and left the "based on…" phrase in the template. Though sometimes cross-category recommendations can be strange. I’m often amazed at things I find in my rec list that have no relation to the things I bought or rated that supposedly triggered the recommendation, simply because those items are popular enough to cut across multiple interests. Of course, right now the only thing they recommend for me in "apparel" is a Darth Vader mask, which I find somewhat disturbing…