Web 2.0 Expo Scribd - the document sharing site that boasts 50 million unique users a month - has told the world that after three years and "multi-millions" of dollars of development on Flash, it's ditching the beleaguered platform in favor of the fledgling HTML5 standard.

Company co-founder and CTO Jared Friedman announced the move this morning at the Web 2.0 Expo in San Francisco, calling it "the largest HTML5 deployment to date." Friedman and crew have already moved 200,000 documents from Flash to HTML5, and eventually, the company will transfer all documents stored on the site, which number in the tens of millions.

Friedman was careful to call Flash "a terrific technology." But somewhere along the line, Scribd realized it's a plug-in. "[Flash] has always had a few drawbacks," he said. "It boils down to the fact that you're putting the content inside a separate application. This leads to a browser-in-a-browser problem where we end up duplicating functionality in the user's browser ourselves.

"This is one, a lot of work, and two, almost incessantly a bad user experience."

Friedman acknowledged that until recently, handling documents in the browser proper wasn't the best option. "The biggest challenge is formatting. Documents use very complex formatting - vector graphics, rotated text, precise positioning - that was difficult to replicate in a webpage," he said. "Browsers only supported a dozen fonts. Without the right font, you can't reproduce the document effectively."

But now that the major browsers have rolled out support for additional fonts through the @font-face element and for vector graphics through either the canvas tag or VML, Friendman says, Scribd believes it can serve 97 per cent of all browsers without Flash. "This even includes IE6," he said. Not even Internet Explorer 9 has embraced the canvas tag, but that's where VML comes in.

Scribd can convert documents originally formatted by Microsoft Office and OpenOffice.org, or in PDF, PostScript, rich text, or plain text formats

Naturally, Friedman demoed his new HTML5 setup on an iPad. The iPad is controlled by a Silicon Valley cult that has a pathological aversion to Flash. ®