Content Recommendation Engine (CRE for short) is a set of modules designed to allow administrators to recommend any personalized pieces of content (whether it be nodes, comments, book pages, or even other users) based solely on voting patterns throughout the site. It does this through a Collaborative Filtering Algorithm called Slope One.

CRE is designed as a out of box solution for end users and also as a developers API. It allows for developers to design plug-ins so that any piece of content on the site can have personalized recommendations.

Because CRE is based on voting patterns it requires VotingAPI module to be installed on the Drupal installation. This allows for a standardized voting system from which CRE draws its information. For more information on VotingAPI please read its documentation.

CRE also requires a voting module that uses VotingAPI based code. There are several different ones available and finding them requires reading their individual documentation. Many of them are listed here .

For an interesting discussion on voting modules read this Lullabot article

What the download can do for site administrators

1. Recommend nodes
2. Recommend certain types of nodes (i.e recommend only stories, or even a CCK node type)
3. Recommend comments when viewing a node
4. Create a list of recommended users

All of this will be explained in further detail in the following pages.