2004: Google unveils Gmail. It will change webmail ... and a few other things as well.

Five years ago, if we wanted to talk to somebody halfway around the world, we'd open up Outlook, Eudora or some other bulky piece of software on our desktops and type an e-mail.

Most of us had webmail, which was a convenience on the road since we could access it from any computer, but it wasn't enjoyable. Web inboxes were slow and cumbersome, messy with checkboxes and radio buttons, and often so riddled with spam they had to be emptied frequently lest they reach capacity.

Gmail changed all that. It was fast and elegant just like a desktop app. There was so much storage, you never had to delete anything. In fact, you couldn't — there wasn't even a Delete button! And you didn't miss the Delete button since it was almost entirely spam-free.

Gmail was so slick and easy to use, many of us switched to it full-time and have never gone back.

On its fifth birthday, it's difficult to ignore the enormous influence Gmail has had not only on web-based e-mail services, but on rich web applications in general. Several of the concepts introduced by Gmail, which were at the time on the bleeding edge of application design, have since been adopted by the web's mainstream.

The biggest was the use of Ajax, a technique for building web interfaces that gave Gmail that extra snappiness, more closely matching the desktop applications it eventually lured us away from.

Before Ajax, users would click a link or a button on a webpage, and then they'd have to wait for the entire page to reload in order to see the result. Using Ajax, web programmers could build an application that redrew pieces of the page on the fly without having to reload the whole thing. A user could see new elements appearing and disappearing on the page as they clicked, minus all the waiting.

The programming technique, which uses JavaScript and had been showing up on smaller, experimental sites for a couple of years, was still untested on major websites. Gmail wasn't the first Ajax website, but it was one of the first to prove it could work on a mass scale.

"When Gmail was written, the term Ajax didn't really exist," says Gmail product manager Keith Coleman.

There was skepticism even within Google, Coleman says. Ajax interfaces were fast, but they required a much larger initial download. Broadband wasn't widespread, so asking users to download a big chunk of JavaScript code over a dial-up connection when they first visited a site was considered a gamble.

But given that Google's audience was rich with web-savvy early adopters, the Gmail team had faith that an Ajax user interface could work.

"The idea of a heavyweight page wasn't so popular, but we decided that the web's most active users already had broadband, and most would in the future," he says. "So we decided it was the right choice for our long-term architecture approach."

Google launched Gmail as a beta product on April 1, 2004, and those early adopters ate it up. The site was invitation-only at first, and you had to know somebody with a Gmail address who had invitations to spare in order to get in. Frantic requests went out over e-mail lists and in web forums. A gmail.com e-mail address soon became a badge of honor among the web's elite.

Also, within months, dozens of other Ajax-driven sites sprung up. The effects also trickled over into Google's other web apps. First, Google Maps, then the Orkut social network, and later Calendar and Google Reader all relied on Ajax-heavy interfaces.

It wasn't long before Ajax became the de facto standard for every other webmail product — Yahoo Mail and Microsoft Hotmail, the other giants of webmail, were later redesigned using Ajax — and for web applications in general.

Productivity apps began to move into the browser, and the only way to urge people to start using them instead of their desktop equivalents was to give these web apps a suitably rich, desktop-like look and feel. Other techniques like Flash and Java had tried and failed, mostly because they were sluggish and required plug-ins. But Ajax was just JavaScript — simple and fast with no plug-in required.

Since then, the bulk of the web has been rewritten for the Ajax age.

Ajax wasn't the only new idea. At launch, every Gmail user got 1 GB of free storage, at the time an unusually large amount — most webmail services offered between 5 and 50 megabytes. Competing webmail providers quickly followed suit, upping their storage amounts to try to match Gmail.

Gmail users also got free auto-forwarding from other accounts and free POP access, which enabled people to check their Gmail accounts from their favorite desktop or mobile client if they wanted to.

The launch wasn't all roses and rainbows, however. Privacy advocates objected to the advertising model, which involves Google's robot eyes scanning every e-mail for keywords and displaying contextual advertisements alongside a user's inbox.

Most users didn't seem to mind, however. After Gmail opened up to everyone in February 2007, its user base ballooned to tens of millions.

Since then, Gmail has grown into a full-fledged platform. There's a contact manager and fully integrated text, video and SMS chat. Users can plug in widgets that help manage tasks, set reminders or just show pictures of their kids.

All the while, the service has remained in beta. Some even contend Google has left the "beta" tag on the Gmail logo as a joke, a nod to its prankish birthday.

"It's not a joke," says Coleman, who insists that Gmail will leave the beta phase once the product reaches some specific milestones as a business.

But what those milestones are, or when it could happen, Coleman wouldn't say.