On Flickr, which Yahoo bought in March, users can organize photos into albums or share them with groups by dragging and dropping them around a page, without reloading the page for each change. "Three or four years ago, this would have been impossible," says Stewart Butterfield, a general manager at Yahoo and co-founder of Flickr. "The experience would have been so bad, it wouldn't have been worth offering this functionality."
Since browser makers aren't racing to push out grand new versions, programmers can for the first time count on the script code and XML they write to run reliably, since the software changes less often. That has pumped up interest in Ajax. "Internet Explorer and [Firefox creator] Mozilla have essentially been in bug-fix mode for the last five years," says Jesse James Garrett, who this year dubbed the new Web-programming approach Ajax and is director of user-experience strategy at Adaptive Path, a Web-design consulting company.
Ajax adherents include Amazon.com, Apple Computer, ING Direct, Lands' End, online DVD rental company Netflix, blog aggregator Technorati, and Volvo. "There's going to be a higher level of trust among management because [Ajax] has validation from companies they trust," says Flickr's Butterfield. "It legitimizes it."
Tech companies are weighing their responses. At its Professional Developers Conference in Los Angeles in September, Microsoft plans to release a preview of Atlas, which the company says will make it easier to develop and test Ajax code for different browsers. "Today, it's a little bit of a hack," Fitzgerald says.
Google last week released an API to its Maps site, which lets developers create "mash-ups" of sites, like a version of the community site Craigslist that includes Google's user interface. The catch is that Google retains the right to advertise on any site that uses its API.
Rivals are poking holes in Ajax. Kevin Lynch, Macromedia's executive VP and chief software architect, says writing Ajax applications requires repetitive testing to iron out bugs caused by different browsers, and he points to a lack of commercial tools. "With Flash, you build once and use the same run time," he says.
James Gosling, a VP and fellow at Sun and inventor of the Java computer language, said recently that while many developers use Ajax and Java in conjunction, Java is a more-productive programming environment. "Ajax is really good for whizzy-looking Web pages," he said. "Google impressed a lot of people with their maps site. What they don't tell people is the amazing amount of pain they went through in trying to make that work on other [browser] platforms."
Ajax is more difficult, but the user experience is worth it, Google's Taylor says. Or, as Sabre user-experience manager Bill Scott puts it, "I know there's a lot of hype, but this is one of the coolest things to come around in a while."