This sounds like a fairly easy optimisation, actually. Whereas a human goes "Oh, so you mentioned A, B, and C, but not the otherwise popular D" and conditions o

This sounds like a fairly easy optimisation, actually. Whereas a human goes "Oh, so you mentioned A, B, and C, but not the otherwise popular D" and conditions on all that information, a simple recommendation system would just go "ah I see you didn't mention popular D, that must be because you don't know about them!" Should be fairly easy to adjust the recommendation system so that it conditions on what you specifically did not mention, assuming that the most popular of that stuff you know about already.