Facebook's new platform becomes mandatory

Since unveiling the makeover seven weeks ago, Facebook had left it up to users to decide whether they wanted to switch over. If they didn't like what they saw, the converts could just click on a link to switch back to the old format.

But that option will be taken away from all users by the end of the week, a shift that Zuckerberg already knows will alienate some of Facebook's audience and raise the risk of driving more traffic to rival social networks like MySpace and Bebo.

"Any change can be a big deal to our users because this is how they connect with their family and friends," Zuckerberg said. "So when you move things around, it can be perceived as being not a positive thing even when it's a positive change."

About 40 million users already have checked out the new design and about 30 million embraced it without reverting to the old look, Zuckerberg said.

But the seeds of an uprising already have been planted on Facebook's own site, where several groups and petitions have cropped up to protest the change.

"It's not that we don't want change, period, it's that we don't like these particular changes," said Scott Sanders, 19, an Austin Peay University student who started one of the petitions opposing the redesign. "You have to navigate more and you have to click more to get to personal profiles. It's too much effort to get to basic information."