Yesterday, Amazon launched Kindle Cloud Reader, a Web browser-based version of its popular e-reading platform.

Built using HTML5, an emerging standard that lets Web applications function like desktop ones, the Kindle Cloud Reader looks and acts a lot like the Kindle apps created for the iPad, Android tablets, and PCs, even offering the ability to store content so it can be read in the browser offline. Experts say the move furthers Amazon’s efforts to make Kindle the dominant standard for e-books.

Amazon’s original Kindle, a device designed specifically for electronic reading, has long enjoyed dominance in the e-reader market. But Amazon has also built an empire that stretches far beyond this one device. The company gives away Kindle apps for a wide variety of devices, including PCs, Macs, Android tablets and phones, Windows Phone 7, Blackberry smart phones and tablets, and the iPad and iPhone. These free apps get readers to expect the Kindle format, and they encourage those who don’t own a Kindle to build up a Kindle library.

The cloud-based app could extend Amazon’s reach farther still. In a statement released at launch, Amazon noted that the Kindle Cloud Reader supports its philosophy of “Buy Once, Read Everywhere.” The Kindle device and related apps all sync with one another via the cloud, so that a user can access her full library—with bookmarks, notes, and highlights intact—from any device.

Much of the early discussion around the launch has focused on the way the new app circumvents Apple’s stringent App Store rules, because it can be accessed via the iPhone or iPad’s browser, and doesn’t need to be approved by Apple. Apple recently limited developers’ ability to take users out of an app—such as by offering a link to make a purchase on Amazon.com. But publishing experts say that focusing on this squabble is shortsighted.

“The Kindle Cloud Reader is a game changer, from my perspective,” says Kassia Krozser, owner of Booksquare, a site that tracks the publishing industry. “What really excites me about this platform is that it is browser-based; it uses the technology that people are using all day long. No special software is needed, no dedicated devices.”

Krozser believes the browser is “the future of reading,” since it gives aficionados the most flexibility and provides a familiar, easy-to-use environment for newcomers to test the waters.

The Kindle Cloud Reader is likely to make things easier for Amazon, too. “Amazon has worked hard to create apps specific to pretty much every platform available, which is one of the biggest reasons I read Kindle books almost exclusively,” says Brian Sawyer, a senior editor at O’Reilly Media who manages the company’s Missing Manuals division. “But it becomes a huge burden—and a losing game—to put this much development effort into every new operating system, especially ones whose user base and outlook [are] questionable.”

The first version of Amazon’s reader is designed primarily for the Safari and Chrome OS browsers, but the company plans to add support for other browsers, including Firefox and Internet Explorer, in the coming months. Sawyer says that once Amazon does this, the availability of Kindle books will leave Apple and other formats “far behind.” He adds, “Amazon’s Kindle platform is indeed becoming the de facto standard for consumer books.”

Despite the likely impact of Cloud Reader, Amazon’s format has its flaws. Michael J. Deluca, cofounder of independent e-bookstore Weightless Books, says that Cloud Reader makes him worry about privacy and control of his own digital assets. Deluca says that the Kindle format limits a publisher’s design options. PDFs, which are by far Weightless’s best-selling format, allow for artistic page designs. However, he notes, “The bottom line is that no matter how we or any small press feels about it, Kindle is already too big to ignore.”

“[As both a publisher and a consumer], I’m disappointed that Amazon decided to try to carve out [its] own format,” says Joe Wikert, who is general manager and publisher at O’Reilly. He says that Epub, a free, open standard supported by many in the publishing industry, offers a richer experience than the Kindle allows.

But Krozser wonders if Amazon will take this opportunity to embrace more-advanced technology. The latest version of Epub, Epub 3, is based on HTML5, she says, and it might make sense for Amazon to abandon its format to make better use of the browser.