What is the best maximum value character count to have in a URL? 100? 200? 255? such as how-many.com/letters-to/have?in=this-url&what=do_you_think?
For technical limitation by the respective browsers: http://www.boutell.com/newfaq/misc/urllength.html Personally, I think that it is best to limit the urls to ten words irregardless of file level and passable parameters.
The best is up to you but : what_people_like.to/see_is_something/they_can_remember_not_5_keyword_stuffed_pages.html Generally you design your sites to be read and viewed by people. It's easier to remember a short page rather then a long one. I'd say 2 keywords for the page name and 1-2 words for the domain.
I wouldn't go above for density and usability. If you go too long it will raparound in the search results and that looks spammy. Also you want something easy to link and copy and paste, or remember. I rarely go past one hyphen between two phrases. But it depends on what you are doing, obviously blogs set to grab the title and turn it into the will have really long urls, and they rank fine.
well that's more of domains, not just permalink structure. this thread is about permalink structures and the length of them...