A reporter uses a cell phone to take a photograph of Google Android 3.0 Honeycomb OS being used on a Motorola Xoon tablet. Mobile app developers are descending on Google I/O, hoping to break it big. - 

Jeff Horwich: By now, you've heard of Instagram, the photo app Facebook bought for a billion dollars. Then there's mobile game Angry Birds, which is creating bundles of cash -- even a movie licensing deal. Today, thousands of would-be app entrepreneurs are descending on the developers' conference known as Google I/O in San Francisco. 

Queena Kim reports.

Queena Kim: Miguel Angel Diez is the founder of Red Karaoke. He’s launching a new version of a sing-along app at Google I/O.

Miguel Angel Diez: Stay tuned, because I hope it’ll be rocking the Google I/O.

The free app is downloaded about 5,000 times a day -- that’s 5,000 people he hopes to convert to paying customers. He considers his ap isp a success.

Peter Farago: We think a great app is about a million daily users or higher.

Peter Farago is V.P. of marketing for Flurry, which tracks about 200,000 apps. For free apps, Farago says “active users” are more important than downloads because most people stop using the average app after a month. Farago says hits like "Angry Bird "are rare. But less popular apps might still find some backing.

Richard Miner is with Google Ventures.

Richard Miner: VCs aren’t necessarily looking for the one-hit wonder.

Miner says they’re looking for a strong team that can bring steady growth.

In San Francisco, I’m Queena Kim for Marketplace.