I'm looking into the viability of using a recommendation system to add additional search results to a users' results list in cases where the search criteria may exclude results because that result does not have up to date data.<p>For example, searching for hotel rooms within a certain price bracket for a certain period and we don't have price and availability data for the period in question.<p>It would use previous searches by all users to show that if your results contain X,Y and Z, it's likely that result A and B would also be of interest. e.g. Previous searches where price and availability data was present.<p>I would think it'd work in a similar fashion to a regular recommendation engine for a shop or news site - if you read / bought these, try these.<p>Currently a Django / Postgresql / Elasticsearch based site
Maybe give PredictionIO a shot? There is a vagrant image that makes it relatively easy to give it a try. It wouldn't help with injecting the recs into search results.
You may also want to mention in your post what languages and frameworks you're already using.<p>If you have a java, scala, or clojure backend, using Mahout to make item to item recommendations is pretty simple to do. If you have a different language, I would just look into libraries for collaborative filtering in that language.