is there a 'proper' way of doing a "you like this, other people who liked this also liked these things so you might like these" query?

I need to produce a list of suggestions for a logged in user. Basically it's "Since you liked these things, and other people who liked those things like these things, so you might like these things too".

I could probably work out a decent algorithm for producing such results, but before I reinvent the wheel, I'm wondering if there is already a common or established method or search algorithm for producing such results?

Any suggestions or advice is greatly appreciated!

typically Apache Mahout is used for such things, see on 'recommendations'