Facebook's News Feed: Behind the scenes of site's changes

(CBS News) On Thursday, when Facebook announced the first major redesign of its popular News Feed, the announcement was the culmination of one long year of work by 70 engineers and designers.

Facebook founder and CEO Mark Zuckerberg said, "News Feed is one of the most important services that we build."

Product marketing manager Kate O'Neill has been logging long days trying to get things just right.

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"News Feed hasn't changed very much since 2006, when it started, and this is just really about making News Feed more enjoyable for people," she said. "We just don't have the option of not moving forward, not modernizing and making the experience better."

At least, that was the message from Facebook members. The social network surveyed hundreds of thousands of users, and many responded with the same request.

Jane Justice Leibrock and her team of researchers also conducted dozens of face to face interviews on the Facebook campus to get feedback from users.

Facebook launches News Feed redesign

"The number one thing that people said they wanted to see was a News Feed that was less cluttered," said Leibrock. "The clutter was this feeling that there was all this different type of news mixed together."

One of the users Leibrock's team met with was Alex Liu. He's been on Facebook since 2004 and says he's "addicted to it".

Liu said his biggest complaint about the social networking site was that he wished "the things that came through on my Facebook feed were just the people that I cared about. I wish I could not see all these different things."

Satisfying heavy users involves a lot of heavy lifting, and that task falls on Facebook's vaunted engineers, like Chris Struhar.

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"We've been working on this for about a year, working 12-16 hour days just sitting in front of our computers and writing code and throwing together these prototypes," Struhar said.

Zuckerberg and vice president of product Chris Cox were updated weekly, and the final result is a News Feed that takes up a larger part of the screen, with bigger pictures and content, while moving everything else to the side.

"Any time that you have a billion people using a product, and many of those people using it every day, you're going to see a diversity of opinion. We know that change can be difficult for people. We're taking a very measured approach here," O'Neill said.

For Facebook, a measured approach means rolling out the News Feed to only a fraction of its users, which still means that several million people are experiencing what 70 Facebook employees have devoted the last year of their lives to creating.

"It's not a question of huge budgets or lots of people, it's a question of really, really focused effort over a year for a very small group of people that did this design," said O'Neill. "But we're just so glad to be at a place where we can start releasing it to people and seeing how they're using it and how they feel about it."

Watch Rebecca Jarvis' full report in the player above.