A recent email on the user-modeling email list is the Artwork Recommender that you can find here. After answering a short questionnaire, you can rate artwork from 1-5 stars, corresponding to “I hate this artwork” to “I like this artwork very much.” Being no artwork expert, I found my ratings of things to be quite biased towards the high end (3/4 stars) - it’s much more difficult to rate artwork than it is to rate movies or songs! They even have the option of saying that you are not interested in a piece of artwork at all, but I never felt like clicking it. Maybe this highlights the difficulty of finding good recommendations: understanding a rating process that users themselves don’t understand. You can also both give an overall rating for items and also rate a particular item in terms of its attributes (artist/material/style).

The website, though, has a neat interface (watch the paintings you rate “fly” into your profile history) and they are looking for participants to add to their dataset, so if you have 5 minutes then go in and rate some 20 or so paintings, help them, and see what comes out…