Bayesian RSS readers?

This is just a quick note wondering why there aren't more RSS readers with Bayesian filtering built in. It would be amazingly easy to let a user define a series of tags and then tag each story appropriately. You could then block stories with certain tags in order to tailor what was shown to you, and allow certain tags to override that and cause an otherwise blocked story to appear.

It seems quite simple really, but I've actually only found one attempt at anything like this, and it's a somewhat imperfect implementation designed for web-based use...it lives at http://www.nullwhore.com/sux0r/index.php.

I'm in the process of training it, but I think the fact that it performs some type of winner-take-all calculation and assigns only one tag to each story is going to hold it back.