HighRanking's forum is really great, some of the forum threads are so basic, that it really makes you think about the fundamentals - which, as many of you know, helps with the more complex areas of a topic. I think that is why many top level professors like to teach the introductory course and the very complex courses. Back on topic...
In a thread at HighRankings, a member asks if there is a difference between having two hyphens in a URL compared to one. Well, a hyphen is considered a space - although the member thinks hyphens are not a space, they are. In the thread, it seems as if, the member feel that two hyphens would make a plus sign. Elementary math, two negatives make a positive ( - * - = +). Wouldn't that be cool?
Anyway, two hyphens just equal two spaces. For example; domain.com/new-york--jets.html would translate to New York Jets. Not sure if you noticed two spaces between "York" and "Jets". But then again, do keywords in URLs help with rankings? That is a debate that has been going on since before SEOs were called SEOs (but back then they did weight in a lot).