During the last take off event, which took place in April 28th at the marvelous universitary city of Coimbra, I had the chance to watch in the first row to João Carvalho presentation, and talk to him later. He is the responsible for the Palco Principal website - a community website that allows Portuguese-spoken bands to interact with users and vice-versa. If you are or understand Portuguese you can access his presentation in PDF format, or the recorded presentation, in MP3.
One of the things that really caught my attention was when João said they use the APRIORI algorithm on Palco Principal for songs and band suggestions in their search system. The APRIORI algorithm is a association rule mining algorithm, this type of algorithm can be very useful in community sites as it allows, for instance, to compare user interests and find the best performing common one between the active user and all the other users that have useful data in the database.
APRIORI its exclusive for best performance top list?
I didn’t quite understand your question.
Do you mean best performance in resource usage or returned results?
Knowledge Discovery in Data Bases contains interesting lectures regarding APRIORI and data mining.
A Java Apriori-T implementation can be found at http://www.csc.liv.ac.uk/~frans/KDD/aprioriTdemo.html
Very nice info at http://www.datastructures.info/ check it out.