The Northern California firm actually rolled out revamped profile pages back in May, having learned from past experience how touchy Facebook members can be about tinkering with their cherished online community's website.
Nearly 30 million of Facebook's more than 100 million users switched to the new format before Wednesday, when the website began forcing the holdouts to adopt the new design.
Forums devoted to savaging the new Facebook format have surfaced on the website and claim thousands of members.
"Life is about change," Nikki Gerwel of Canada wrote in a 'Who hates the new Facebook format' forum on Wednesday. "But I like good change, not crappy change ... the changes are horrible."
The new design lets Facebook members use tabs to give priority to fresh pictures, messages, or "feeds" on main profile pages and compartmentalize mini-applications and "static" information such as curriculum vitae.
The changes are motivated by feedback from users as well as a trend toward people flooding the Internet with videos, pictures, and musings they want to instantly share, said Facebook vice president of marketing Chamath Palihapitiya.
"We want to make sure it is easy for people to push and pull information in the form of bite-size content rather quickly," Palihapitiya said while unveiling the redesign at Facebook's office in Palo Alto, California.
Popular mini-applications such as "walls" and "graffiti" were preserved.
Facebook maintains that the changes make pages livelier and better organized while giving people more control over software applications they opt to install.
"We understand that some people are unhappy or concerned about the recent changes to Facebook," a customer support representative at the website wrote in a posted message.
"We think, however, that once you become familiar with the new layout and features, you will find these changes just as useful as past improvements."
Facebook engineer Mark Slee earlier told AFP that the website's team is confident they can win over their users.
"We don't look at this through the lens of messing with something that works," Slee said. "We are focusing on innovating and making the product better."