Sometimes tech companies open little satellite offices because they recruited a hotshot who doesn't want to move to the mother ship.

On the surface, it looks like Yahoo did that when it hired Dave Sobeski away from Microsoft last November and set him up in a Bellevue office.

It also seems like a Googlesque tactic to lure more talent from Microsoft.

But Sobeski, while finally confirming today the company's expansion here in the Puget Sound region, said there's much more to the story.

Yahoo's going big in Bellevue, where it will work on one of the three pillars of the company's new strategy, according to Sobeski, senior vice president of platforms and architecture:

"We want to build a big presence up here. We want to be one of the top employers up here and have people excited about Yahoo up here."

Sobeski wouldn't provide growth projections, but he confirmed that the 115,000 square feet on three floors that the company leased in the One Twelfth@Twelfth building can accommodate 500 to 600 people:

"We wanted to ensure we had space to grow. We'll figure out how to grow it and what the plan will be.''

What will the office be like two years from now?

"We should be able to grow that talent pool rather rapidly.''

Yahoo now has about 50 employees in another floor, while the former Nortel Networks space it leased are given the funky Yahoo touch. "We are Yahooizing the workspace," Sobeski said.

Those 50 employees mostly come from a previous Seattle sales office and a small Eastside data-mining company that Yahoo acquired.

Sobeski said he's hearing from former co-workers at Microsoft, where he worked nearly 14 years on products ranging from Visual Basic and Internet Explorer to Windows Vista.

But he's also hoping to attract stars from Amazon.com, Adobe, the University of Washington and smaller companies in the area.

Exactly what he'll do in Bellevue is sort of secret, but Sobeski's enthusiastic about the opportunity to help further transform Yahoo into a platform for developers.

Sobeski noted that reaching out to developers is one of the major priorities outlined by Chief Executive Jerry Yang, along with serving as a great launching point for the Web and connecting advertisers and publishers.

From Sobeski:

"One of the things we definitely think about is how do we turn things into a platform, how do we go build that great ecosystem. You want to go build great software for your customer. How do you enable that? You enable that by allowing us to build that stuff but (also) by enabling third parties, publishers, to go build that stuff."

Yahoo can also do that by "having a platformy like guy like myself come in and say we definitely want to go look at everything we do and make sure we do it at great scale, we standardize it, we expose it to people ... getting that mentality throughout the company."

Will Yahoo provide hosted developer services similar to Amazon's Web Services? Sobeski's answer sounds like a strong maybe:

"We won't say no and we're not officialy saying yes but we believe it's interesting."

Bellevue should thank Sobeski's girlfriend, by the way.

When he was being recruited by Yahoo, he considered moving to its headquarters in Sunnyvale, Calif., but he wanted to stay close to her. They've been together for four years and she has a good job at Microsoft, so he chose not to relocate.

But it turned out there were already people at Yahoo pushing to expand in the area.

"It wasn't actually me coming that got the ball rolling, there were other people that said hey, there's talent."

He reiterated that point several times: the main reason for a Bellevue office is to attract software developers who can help build the Yahoo platform:

"We're going to go build the right technologies up here and the right services. What is up here is just the talent that we care about, which is really technical people who can solve problems fast and efficiently. That's what you want."