This module adds two blocks:
To make the recommendations, the module uses the {history} table that keeps track of 30 days of users' node browsing history. Also, when you enable the "boost comments" option, the module then takes users' commenting history as browsing history as well.
The "Recommended for you" block provide personalized node recommendations based on a user's node browsing history. The basic idea is that, for example, user A browsed node X, Y, where users who browsed X, Y also browsed W, V; then "Recommended for you" would display W, V for A.
This module requires Recommender API at http://drupal.org/project/recommender, which provides the core matrix computation functions. The recommendation quality/accuracy are the job of Recommender API.
After install/enable/setup, please go to admin/settings/recommender to generate the recommendations offline.