A big problem with these tools is that very few will abandon this place for a slightly ugly replacement, even if it does offer something somewhat useful. If you

A big problem with these tools is that very few will abandon this place for a slightly ugly replacement, even if it does offer something somewhat useful. If you provide an API, someone might write a script/bookmark that added the percentages to the posts here, or color coded them. Are you training on comments as well? My bet is that the comments section will be more useful for this than the actual article. Incidentally, I really wish that upvotes and the like were publicly visible. This would surely result in a similar tool, but for a recommendation system.