Confirmed: Marketplace will be the only way to get apps on Windows Phone 7 Series

We just got out of a meeting with Microsoft's Todd Biggs, who dropped a little bombshell on us: the only official way to get apps on a Windows Phone 7 Series device will be to download them from the just-detailed Windows Phone Marketplace. That means developers will have to abide by Microsoft's technical and content guidelines in order to make it in, with the very real possibility of rejection -- sound familiar? Todd told us Microsoft plans to avoid Apple-style submission headaches by making the process transparent and predictable, with a group of Microsoft execs regularly meeting to examine edge cases and refine the guidelines as needed, but even the best intentions can be led astray by a sexy app or two. We also got some additional details on Marketplace and how it's going to work, catch the highlights after the break.

Update: Microsoft wanted us to clarify that enterprise customers will be able to deploy apps to employees outside the consumer-facing Marketplace -- details on that will be released in the future.

  • Windows Phone Marketplace appears to take some of the best parts of the App Store and the Android Market and throw them together into a hodgepodge, but they've strayed a bit with the trial period system -- with the Marketplace, it's up to the developer to decide how the trial works. There are API hooks to let the developer manage the whole process, actually -- to quote Biggs, a game dev could end the trial after you've killed 50 trolls, for example. There's no additional download after the trial expires; the game just unlocks if you choose to buy it.

  • Marketplace membership for developers still costs $99 a year, though Biggs says they're looking at tweaking the 5-app limit per account present in 6.5 -- whether that means they'll remove the limit altogether, though, we don't yet know.

  • There are no fees for developers to update their apps, nor fees for users to download them.

  • Speaking of user downloads, you'll be able to uninstall purchased apps and redownload them at a later time at your leisure -- the purchases are tied to your Live account, not your phone, so you can move between devices at will. That's a Microsoft policy that developers won't be able to override.

  • If a dev wants to post a free, ad-supported app, they've only got two hurdles: the $99 fee and -- of course -- approval by Microsoft. For ad-supported apps specifically, the company will have some guidelines specifically targeted at making sure the ads are appropriate and germane.

  • Microsoft's only dealing in real money here -- no points (though there's still an opportunity for direct carrier billing).

  • Though there's some development synergy between Zune and WP7S at this point (with XNA, specifically), there's no ecosystem synergy beyond that -- different marketplaces for the developers to submit to and manage.

  • You'll be able to browse and buy apps and games through the Zune desktop client on your PC.

  • Though there's no way for end users to purchase and install apps outside of the Marketplace, Microsoft is naturally working on a solution for trialling apps on a limited number of devices; if we had to guess, it'll be something akin to Apple's ad hoc installation mode, but Charlie Kindel has said that it won't be available in the first release of the platform. For now, the only way to do it is to unlock devices one at a time through the developer portal, and Microsoft isn't talking about how many devices you'll be able to unlock on an account right now.

On several occasions, Biggs stressed that the company will be publishing comprehensive policies and guidelines in May, so that should fill in any blanks we've still got by then.