Welcome to Web 3.0

At All Things Digital World Headquarters*, our huge staff of expert analysts** is always keeping track of two things: The latest trends in tech and media, and the latest jargon used to hype those trends.

This year, as we convene the seventh edition of D: All Things Digital, we think something major is happening at the intersection of tech and media, and we think it deserves its own new hyped-up name: Web 3.0. Yes, folks, we are declaring the Web 2.0 era over, because, well, when you run conferences and Web sites, you can say stuff like that.

But, if you read on a bit, you will see that we actually have some real, rational basis for believing that yet another seminal moment has arrived in the never-ending digital revolution that inspired us to launch this gathering. And, as you will observe over the next few days, we have assembled what we think is a stellar lineup of speakers to address this major change and other topics.

First, though, a few words about the elephant in the ballroom: The Great Recession. Or, as we like to call it on the AllThingsD.com Web site: The Econalypse. We started work on launching D during the last tech bust, and we believed then that — despite the very real economic woes afflicting the industry–the digital tidal wave sweeping the world wasn’t stopping. In fact, it was during that last recession that the iPod, iTunes, Windows XP, Mac OS X and early social networking services, like Friendster and LinkedIn, were born.

We are painfully aware that this crisis is far worse–we work at a media company, after all, and media companies have been economic piñatas lately. We do not in any way underestimate the economic pain and danger still under way all over the world. But we still believe the digital tidal wave rolls on. And we are immensely grateful to all of you for continuing to attend D under these tough circumstances. In fact, your support has been so strong that we actually sold out a few days earlier this year than last.

So what’s the seminal development that’s ushering in the era of Web 3.0? It’s the real arrival, after years of false predictions, of the thin client, running clean, simple software, against cloud-based data and services. The poster children for this new era have been the Apple iPhone and iPod Touch, which have sold 37 million units in less than two years and attracted 35,000 apps and one billion app downloads in just nine months.

The excitement and energy around the iPhone and the Touch–and the software and services being written for them–remind us of the formative years of the PC and PC software, in the early 1980s, or the early days of the Web in the mid-1990s.

It’s a big deal.

But this is not just about one company, one platform or even one form factor. No, this new phenomenon is about handheld computers from many companies, with software platforms and distribution mechanisms tightly tied to cloud-based services, whether they are multi-player games, e-commerce offerings or corporate databases.

Already Palm, Research in Motion, Nokia, Microsoft and others are hot on Apple’s tail. You will hear from them here at D. And a profusion of new devices, software development kits, app stores and cloud-based services has been announced in the teeth of the economic downturn.

Some of these handheld computers will make phone calls, but others won’t. Some will fit in a pocket, but others will be tablets or even laptop-type clamshells. But, like the iPhone, all will be fusions of clever new hardware, innovative client software and powerful server-based components.

And media companies are on the case, too. You can already read The Wall Street Journal and other news sources, complete with photos and videos, on the iPhone, the BlackBerry and the Kindle, and new handheld devices are coming that are tailored to news. Our own AllThingsD iPhone app will be out by the time you read this. And consumers can stream radio and TV, and even follow live sports events, on pocket devices.

Over the next few days, you’ll hear from Microsoft CEO Steve Ballmer, whose company makes software for both the new platforms and the traditional PCs they threaten. And the leaders of the hottest social network, Twitter, Evan Williams and Biz Stone, will talk about its future. Speaking of the future of social networking, we have invited News Corp. digital head Jon Miller and MySpace CEO Owen Van Natta, who were recently brought in to reinvigorate the media giant’s business, to talk about how they plan to do just that.

You’ll hear from new Yahoo CEO Carol Bartz, who’s trying to deal with rivals and suitors just as the new era is dawning. Also on stage will be the leaders of some key companies making the handheld computers’ hardware and software: Mike Lazaridis of RIM; Jon Rubinstein and Roger McNamee of Palm; and Olli-Pekka Kallasvuo of the worldwide mobile phone leader, Nokia.

From the telecom side, there’ll be Randall Stephenson of AT&T. Cable pioneer and media mogul John Malone will offer his perspective on the future of television.

And, from the content world, we’ll have Jeff Zucker of NBC, Irving Azoff of Ticketmaster, Mark Cuban of HDNet, blogging queen Arianna Huffington and Washington Post publisher Katharine Weymouth.

The leaders of Mozilla, Mitchell Baker and John Lilly, will talk about the role of Web browsers and open source. And playwright Eve Ensler will explain how all this shiny technology is tied, unwittingly, to a crisis thousands of miles away.

So sit back, open your minds, and get ready for Web 3.0.

*Actually, just a cottage in back of Kara’s house.

**Actually, just a handful of journalists, a couple of editors, a geek and an intern, plus some business people.