In his inimitable style, Tim O'Reilly tells us why GMail matters. The piece is entitled, "The Fuss About GMail" but that doesn't begin to properly identify the real meat of what Tim's saying. For example, here's one part I found surprising:

Pioneers like Google are remaking the computing industry before our eyes. Google of course isn't one computer -- it's a hundred thousand computers, by report -- but to the user, it appears as one. Our personal computers, our phones, and even our cars, increasingly need to be thought of as access and local storage devices. The services that matter are all going to run on the global virtual computer that the internet is becoming.

Until I heard about gmail, I was convinced that the future "internet operating system" would have the same characteristics as Linux and the Internet. That is, it would be a network-oriented operating system, consisting of what David Weinberger calls "small pieces loosely joined" (or more recently and more cogently, a "world of ends"). I saw this as an alternative to operating systems that work on the "one ring to rule them all principle" -- a monolithic architecture where the application space is inextricably linked with the operating system control layers. But gmail, in some sense, shows us that once storage and bandwidth become cheap enough, a more tightly coupled, centralized architecture is a real alternative, even on the internet.

From O'Reilly Network: The Fuss About Gmail and Privacy: Nine Reasons Why It's Bogus [Apr. 16, 2004]
Referenced Fri Apr 16 2004 12:28:54 GMT-0600

I have to admit, when I first heard about GMail, my response was "so what?" since there are already so many free, hosted email solutions, but size does matter and 1Gb of storage for mail changes some things. Most importantly, it makes smart searching and analysis of email possible. For Google to make that work, they need lots of mail on their servers and this gives them that. This is an example of where "more of the same" enables dramtically different results.