With the iPad 2, Steve Jobs has literally doubled-down Apple’s advantage in the tablet game. While the rest of the pack continues to scramble to keep up, the iPad 2 added just enough feature freshness to maintain its lead. If Apple’s innovation and marketing fade with a weakened Jobs, the company is always ready to lawyer-up to defend its advantage. (This just in: Apple announced it is suing Samsung for patent violation and design plagiarism on the iPad and iPhone.)

Apple’s biggest business challenge is keeping up with demand. Tim Cook, Apple’s chief operating officer, told analysts this week that the company is facing the “mother of all backlogs” with the iPad 2. That’s a problem the other tablet players don’t even worry about. How many people have you heard say, “Forget the iPad, I’ve got to get a Xoom or a Galaxy!” Not many, I’ll bet. There’s no denying the seductive power of Apple’s cool factor and marketing savvy.

In the tablet race, Apple is lapping the field right now but the race is far from over. Apple’s sustainable advantage isn’t its technology (unless its lawyers successfully trip-up the competition). The real Apple core is its iTunes engine powering the AppStore. The 65,000 iPad apps and 350,000 iPhone apps dwarf the other platforms. Apple also has enjoyed a four-year head start in the app race.

This is all about to change. The reason is HTML5. It’s the great equaliser that makes it possible to create spectacular apps in a Web browser. With HTML5, apps are freed from the confines of the AppStore while providing everything Flash does — with the promise of less power consumption on mobile devices, too. Since HTML5 apps avoid the AppStore landlord’s cut, you could say that they are automatically 30% better for publishers.

What is this new magical elixir? Let me get the technical definition quickly out of the way. HTML5 is the fifth generation of the programming language that defines what we experience on the World Wide Web: the Hypertext Markup Language (HTML). Within the last several weeks, the major Web browsers (Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, Opera and, yes, Apple Safari) all released new versions with support for HTML5.

HTML5 is a breakthrough that makes it possible to create pure open-source Web apps that look and feel like AppStore apps. Let’s call it ’appiness — the essence of what makes an app “magical and delightful,” to quote the latest Apple iPad 2 TV ad. Defining magic is easier said than programmed. Penn and Teller revealed the secrets behind magician’s tricks, which spoiled a little bit of the fun. For their next act, I hope they take on the secrets behind a spectacularly successful app. Who could have predicted that Angry Birds would become a global cultural obsession?

Defining ’appiness means distilling the digital user experience into something magical and delightful. HTML5 is a breakthrough, but it won’t deliver blockbuster apps out of the box and it may not take us to that elusive rarified state of ’appiness. HTML5 will change the perception that apps are defined by whether they live in the AppStore (or AppWorld or Android Market). Think of HTML5 as a do-over that frees publishers from the grip of the landlord. That should make us all ’appy.

Bonus Feature: Want to see an extreme example of what can be created with HTML5? Experience this interactive Web film: Arcade Fire The Wilderness Downtown.