Just because it's never worked as a movie recommendation system doesn't discourage me from trying it for a commenting system! (Especially since the idea is so trivial, and ought to be easy to implement).
Well, how would you display these recommended comments? How would you analyze the content of comments to determine recommendation? If I downvote every anti-Linux comment I see, does the algorithm stop showing me anti-Linux comments? Because that detracts from the debate going on. What if I downvote based on poor spellings - or even more, if I downvote solely based on how well the writer forms sentences? How will the algorithm figure that out?
The easiest solutions are the simplest ones. Complexity only serves a purpose when there's a simple cause behind the complexity. Adding algorithms when there's no need will only make things less reliable.
