I think you have almost already solved it [1]. You may think of having a pin tag with a small cross (while the mouse hovers). If you see, people clicking the crosses often it's a good feedback that the tag may be wrong. It can help you correct these tags if not appropriate.
In addition, you should also think about adding tags for CAM RIP, BR RIP, DVD RIP etc. Movie torrent downloaders do care about such information.
The crosses are a nice idea, although we'll be hard at work at improving our algorithm first (one guy in the team is fulltime on that) and see how it goes.
We'll try to get as much as we can right by default until we ask for help from users :)
I would be curious to know what kind of algorithms you would be looking at. I am a researcher with research interests in "text analytics" and "social media" & if works well I would be glad to contribute.
We're currently working on an algorithm based on multiple criteria like filesize, quality, release group...
Our first goal is to find the best torrent for a chosen movie.
Maybe we'll use social medias for movie matching.
Displaying by default would confuse lambda users. How would you solve it UX-wise?