Multi-attribute content search and filtering. In some systems, users can explicitly provide their general preferences on multi-attribute content of items that can be
used by various searching and filtering techniques to find the most relevant items.
For example, in [82] users can identify the movie genre, MPAA rating, and film
length that they like and specify which attribute is the most important for their decision in choosing the movies at the current time. Then the recommender system
narrows down the possible choices by searching for the items that match these additional explicit user preferences. For example, if a user indicates that she wants to
watch “comedy” movies and the movie genre is the most important attribute for her,
she will be recommended only comedy movies. Similarly, in [45], users also can
provide to the recommender system both the preferred specifications for different
content attributes as well as the corresponding importance weights for the different
attributes.