I think people just want to be able to use an address like www.mysite.com/myproduct without having to write the extension.  Non tech users can remember that easily, once you tell them the extension they may have to pull pen and paper to write it down (yes there are people like that).  In addition, another example is that you may want to define multiple addresses for the most popular products in your lineup, once users see this once they will intuitively use other words.  See the addresses below, I use them all the time, they are a lot easier to remember than the actual URL they take you to.

www.microsoft.com/sql
www.microsoft.com/vs
www.microsoft.com/net
www.microsoft.com/office
www.microsoft.com/msdn
www.microsoft.com/technet

I actually wish DNN could do that (on a per portal basis).

Carlos

PS  Forgot to add, if aspx is the default extension why the need to write it right?

I disagree, those are not just simple subfolders, but if it makes you happy to explain it that way that's fine too.  I also know how IIS works and you are so full of yourself that you cannot respect others peoples opinions and it blocks your ability to see new ideas.  I know that "microsoft.com/sql" is not the same as http://www.foo.bar/tabid/documentid/p..., I made my post within the context of DNN and that long string is exactly part of the issue.  Again, you are so fixated in correcting people (usual in your posts) that you totally miss the point.  And that is exactly the point, the short version is easier for non-geeks like you to remember.  I don't care about SEO "experts" either by the way, and I did not mention any in my post.  I was talking about a usability idea and I agree with you in your last sentence, even when you seem to contradict yourself.  Nobody cares about the technology behind the page, so why the need to have to write the ASP.Net specific extension.