Ask HN: Can you Recommend a good Recommendation Engine?

I am writing a proposal for a company that has a lot of data in all forms, text, video (youtube I think and others), mp3 and wants to index it and make it relevant to searchers. For example, if a cook signs up, they get all the data related to being a cheif including how to take care of burns, fires, or things like that that don't necessarily have the word cook in it. I need some good resources or a starting point so I can research this and put something together for them. Any help would be very very welcome!

They suggested Sitecore’s Content Management Solutions tool but I've never heard of it.