After giving a lot of thought into the "keywords/title in a url" concept, I actually kind of like it; especially from a user perspective as it can be a lot easier to distinguish differant saved URLs; though one thing that's gotten to me is that SE's don't like duplicate content, not to mention if we're using the subject in a url theres not much to stop other topics from having the same keyword, so it should be something like:
ubbthreads.php/ubb/showflat/number/183930/page/1/subject.html
Then you're just having the keywords there as dummy data. I do miss having the "fake html" extension like what Classic had.
