As I posted yesterday, I don't see the notion of hiding the browser URL bar as particularly revolutionary, although some users will doubtless appreciate it (just as some choose to autohide their Windows taskbar or Mac dock). However, it does point to a larger question: are URLs themselves an outdated mechanism for referencing websites?
On the positive side, URLs provide a short and (sometimes) memorable way to go straight to a specific webpage. But they are annoyingly arbitrary. Why does a freeware joint called Acme Laboratories get to have www.acme.com when they are eclipsed by a number of sites in the Google rankings for "acme" (and there are doubtless tens of thousands of other companies of that name nipping at their heels)? For that matter, why does my company have to settle for www.salsitasoft.com when there is nothing at all on www.salsita.com?
URLs are clearly not ideal, but none of the alternatives are perfect either. Google search results are more democratic, as they are heavily weighted towards sites that are linked to by others (and the same is nowadays true of other search engines as well). We probably don't want to make a single company or handful of companies the official phone book of the web though. And it's still easier for many companies (again, like my own) to give out their URL than to tell people to search for them on Google and click on the 10th (or 33rd or 127th) hit.
I don't doubt that we'll come up with a better approach someday, but for the time being URLs seem like a decent solution. Like real estate, the initial allocation of scarce resources might seem unfair, but market economics provide an efficient way to price and distribute them subsequently. After all, I can always go out and buy www.salsitasoft.com if I decide it's worth it. And if a future innovation renders URls irrelevant, there's no monopoly power or other coercive force to prevent it from taking hold.