Au contraire, you can do exactly this with an IDRescorer. Divide by (the log of) and item's occurrences for example to penalize popular items.
I don't recommend this. Stuff like the log-likelihood metric is already in a sense accounting for things that are just generally popular and normalizing that away. On Sun, Mar 25, 2012 at 1:52 PM, Steven Bourke <[email protected]> wrote: > You could just penalise popular items and promote rarer items from a users > top100 recommendation list. Nothing in mahout is geared towards > serendipity, novelty or diversity which appear to be this years interest at > recsys (recsys.acm.org). But the jist is that its very difficult to do > right because if you get it wrong the recommendation could really irke the > user.
