Last week, Microsoft made huge waves when it announced that its long-proprietary .Net application framework was now available as open source, completely rocking the Redmond, Wash., giant's cross-platform strategy and public image, all in one fell swoop.

It's the latest, and arguably the biggest shift in strategy for Microsoft as new CEO Satya Nadella steers the company away from its proprietary past toward a future as an open services platform.

This week is the TopCoder Open, which, for competitive coders, is like the World Series or the International, depending on how nerdy you are, with 1,400 developers in attendance and $260,000 worth of prizes on the line. Microsoft's developer evangelist Matt Thompson took the stage to talk about the kinder, gentler Microsoft and why students, startups and anybody with an interest in coding should take the company seriously.

"Nobody loves developers more than us," Thompson said to the packed crowd.

Thompson came to the TopCoder Open with the goal of getting developers to take Microsoft's platform at least as seriously as they do Amazon's, Google's and Salesforce's. The net result of Thompson's presentation: A pretty decent sales pitch for working on the Microsoft platform and a lot of un-Microsoft-like talk about the importance of sharing, working together and open source.

Thompson began his presentation with some of his personal history. He was an evangelist for Java at Sun Microsystems; a platform and API developer at early mobile startups General Magic and Taligent; and a mobile developer besides. If there's a trend he's noticed in his career, he said, it's that coding is getting easier thanks to modern development tools, and that code literacy is going to be more crucial than ever as a basic life skill.

As mobile and social experiences continue to dominate more of our daily lives, he said, opportunity is increasingly going to come in the form of new software. That's why hackers and makers are the vanguard of the new wave of developers, he said.

"Coding is the easiest way to express new ideas," Thompson said.

Which is why startups need to consider Microsoft. Thanks to the new Visual Studio Community Edition, teams of fewer than five can use Microsoft's development environment to build those new ideas together and have them work across platforms.

Because Microsoft is, you know, Microsoft, it has something for everybody. Deploy your .Net app on Microsoft Windows Azure and scale up (maybe even for free, if you qualify for the Microsoft BizSpark program). That app can run on iOS, Android or Windows Phone, which heaven knows needs apps (or euthanasia, depending who you ask). Given the entire terrible majesty of the Microsoft ecosystem, it's a path leading from a startup with a $1 billion idea to an enterprise with a $1 billion bottom line, Thompson said.

And the way to get there, he said, is with openness and open technologies -- a rising tide lifts all ships, and Microsoft wants to help all developers succeed no matter what technologies they use. Getting a billion-dollar idea to market is easier when you can stand on the shoulders of giants.

"It's no longer monolithic or proprietary," Thompson said. "It's about sharing."

Un-Microsoft-like, indeed. But maybe the surest sign yet that Microsoft is rethinking its relationships with developers. Which is a good thing, because if Microsoft is serious about this "platform," developers are going to be its most precious resource, and it has some image rehabilitation to do. In that light, having startups and independent coders at one of the premiere events for the same is a shrewd move.