Recommender applications currently use a wide range of input data in forming their recommendations, including explicit ratings and
simple behavioral data such as purchases and click-throughs. However, there are many other types of data that can be collected and
used. In the future, recommender systems will commonly collect dozens of different types of data and integrate them into effective
recommendations. Ongoing research in web usage mining and more general commerce-related data mining may reveal techniques
for exploiting complex behavioral data.