SlideShare ditches Flash, rebuilds entire site in HTML5

SlideShare, the website for sharing PowerPoint presentations and other documents, has had a major makeover. The company has ditched Adobe Flash (s adbe) technology entirely, and rebuilt its website using the HTML5 markup language, SlideShare co-founder and CTO Jon Boutelle will announce at GigaOM’s Mobilize conference Tuesday.

This means that SlideShare is now viewable on every kind of mobile device, from iPads to iPhones to Android devices and beyond. Another perk is that the website is now 30 percent faster and its files take up 40 percent less space than they used to. Search engines can now read the content within SlideShare slides, meaning that presentations hosted there should start to get much higher page rankings on sites like Google. Text within documents can now be copied and pasted, as well.

The web as “the biggest app store of all”

SlideShare initially set out to build its mobile experience by making individual apps for the Apple store, the Android (s GOOG) marketplace, and others, but quickly realized that in the long term such a strategy would not be sustainable. “If we committed to app stores in general, it would really end up fragmenting our engineering team and our engineering efforts,” Boutelle said in an interview Monday. “We were trying to find an alternative, and the answer is that HTML5 can work on all of these devices. Now the way we frame our thinking is that the web is the biggest app store of all.”

Screenshot of SlideShare's homepage on the iPad (click to enlarge)

Starting Tuesday, SlideShare’s site will be displayed in HTML5 on both desktop and mobile devices, and all new documents added to the site will be rendered in HTML5. Over the next several weeks, the company will be porting its entire back catalog of five years’ worth of presentations to HTML5. SlideShare expects the conversion to finish by year’s end, Boutelle said.

A huge engineering project

Making the big switch has not been easy. SlideShare has 50 employees, the majority of whom are engineers, and all hands were on deck over the past six months to work on converting the site from Flash to HTML5. “This is the hardest thing we’ve ever done,” Boutelle said. But that difficulty should not be apparent to the average SlideShare user (the site receives 60 million unique visitors per month.) “The change is so structural that if we’ve done it right, people will just know that SlideShare is better, but they won’t know why.”

SlideShare is certainly not alone in doubling down on HTML5. Facebook’s new Timeline interface relies heavily on HTML5, and the company’s CTO Bret Taylor has said that the markup language will be a huge part of the company’s development efforts going forward. Apple (s AAPL) has been one of HTML5’s biggest proponents, as has Google. But it’s shaping up to be even more interesting to watch how smaller companies like SlideShare adopt the platform for their own products.