I'm not saying that URLs are superfluous. But I think their function is exaggerated. Especially when it comes to Web Apps, but even in the case of articles in which hyperlinks are really useful and used a lot. They often seem like C pointers on which you better don't do any arithmetics. But unlike C pointers, often I cannot dereference them. ;)

Around '99 I did not rely on bookmarks, instead I saved interesting articles to my hard drive because links would break so often. Even today the problem remains and I don't even dare to say whether it got better or worse.

Maybe there are smarter concepts than HTTP-style URLs that we are not aware of yet. Might be also interesting regarding privacy, because many people actually do not want static hyperlinks to their personal information that last a million years.