Goodbye PC, hello smartphone

The era of the PC's dominance is officially over. We have crossed over into the age of mobile computing.

This transition has been building momentum for a while. Some might argue that the iPhone was the dawn of this era. Others might say it was really the rise of the BlackBerry. Or maybe even Android, Google's mobile operating system. Good cases could be made that any one of these marked the start of the mobile era.

But Microsoft's announcement of its new mobile phone platform this week signals a clear end to the old PC era and an epic shift in computing.

But why Microsoft? The reason has less to do with the details of Windows Phone Series 7 that the company unveiled at the Mobile World Congress in Barcelona, Spain, on Monday.

I haven't touched it, and it won't be available to consumers for months.

But this isn't about specific features or its design, or whether it will help Microsoft regain lost momentum in the mobile market. Rather, what struck me is how Microsoft did this.

For years, the company took its Windows operating system and created a miniature version for smartphones. While initially good enough for many users, this was the approach of a titan aimed at protecting its turf, rather than a nimble tech firm trying to innovate. It was safe, which is often the enemy of creativity.

Along the way, Windows Mobile was surpassed by the iPhone, Android and Palm's WebOS in terms of elegance and features.

Rapidlylosing market share in this critical space to those competitors, Microsoft eventually decided it was time to reboot. For the new version, Microsoft scrapped the Windows-based version completely. The need to think mobile first was so critical, the company was willing to risk undermining its biggest franchise, Windows, which brings in billions of dollars a year.

Rather than let that fear of change paralyze it, Microsoft built the new operating system for smartphones from the ground up. And it did it for the right reason:

"The phone is not a PC," said Joe Belfiore, Microsoft's corporate vice president of Windows phone program management as he demonstrated the new platform.

"Well, duh," you say. That sounds obvious. It's not.

The success of the Windows operating system bred complacency. The temptation is to make sure everything you do reinforces the cash cow.

To cast that aside, to start over, is a fearless move.

I chatted with Karen Wong-Duncan, a manager in Microsoft's mobile communications systems, on Tuesday, who said the rapid change and adoption in the smartphone market required more than just incremental changes. This time around, Microsoft was trying to think big.

"If you look at the investment that's been made in this, it's not a 'toe-in-the-water' investment," said Wong-Duncan. "We're going to dive right in."

This comes just months after Microsoft released Windows 7, a well-received update that has helped heal some of the bruises from the ill-fated Windows Vista. Even with all that money and development effort poured into Windows 7, the company still decided to build something separate and different for the mobile market.

Of course, Microsoft's new software is just the latest big announcement in what is shaping up to be the Year of Mobile. Google kicked things off with the debut of its Nexus One smartphone. And Apple nudged things along during its press conference for the iPad, where it took great pains to define itself as a mobile company.

Will Microsoft's mobile restart be enough? And how will the features stack up against the iPhone and Android? While the initial reaction has been positive for Microsoft, I'm not really thinking about that right now. The new platform won't be available for several months, an eternity in the smartphone race.

What matters to me is that the company whose success is so closely associated with the personal computer has made a clean break from the past to take a radical step forward.

I'm not saying we won't still have desktop computers. But if you're looking for the real action, the exciting innovations, it's going to be in mobile from now on.