[Updated at 10:11 PST on Dec. 6, 2011 to add response from Facebook.]

Facebook launched Sunday the “New Profile,” a completely redesigned user profile that highlights more basic personal information on the front page and continues the site’s growing focus on documenting real-life user relationships.

Any user can immediately upgrade to the new profile design on this page.

The most obvious change is a brief, basic bio that appears top and center underneath the user’s name. This bio includes your employer, education, hometown, current city, and spoken languages. Facebook, always encouraging its users to add more data to the site, will display messages to the user like “Add your current work information” or “Add languages you speak” if you haven’t added this information already.

Beneath the bio is a new strip of five of your most recent photos, an effort to make user profiles more timely. (Having learned from experience, Facebook is quick to ensure that “your privacy settings have not changed” when introducing this new section. It’s true, your friends can’t see any new photos they couldn’t see before.)

The other big change is purely navigational. Instead of having tabs near the top of the profile to switch between the wall, photos and other pages, these buttons now appear on the left-hand side, under the main profile picture.

There are some other minor changes as well. When visiting another user’s profile, a little box on the top of the right-hand pane now features similarities and shared interests between the two friends. For example, my friend Meryl and I are in 320 photos together, we have 132 mutual friends, are in two groups together, and have a few shared music interests.

Predictably enough, user reception has been the opposite of warm. A quick glance at either comments on Facebook’s blog post announcement or a Twitter search for "Facebook profile" brings back memories of other similarly large-scale site changes, like the introduction of the News Feed, which elicited negative responses from the benign to the apocalyptic.

“If you dont fix this mess, could be the end of facebook!!!” writes one commenter, Helena Perestroika, with two up votes backing her up. Two other commenters, each with three up votes, requested a way to restore their profiles to their original form.

Personally, I was curious why Facebook used a different procedure this time when introducing the upgrade to users. Normally, Web services roll out services of this magnitude gradually to users, iterating and responding to user feedback at each successive step. This is how Twitter rolled out its site redesign #NewTwitter and it’s how Facebook is currently rolling out its new comprehensive messaging system. When a Web company wants to get something right, it takes its time, listening to users, sometimes even A/B testing, to avoid widespread anger from the masses.

I contacted Facebook to see if they would share their rationale for making the profile upgrade opt-in for all users immediately, and they responded:

We want to give people the ability to upgrade to their new Profile over time, walk them through the process and give them the information they need to make the change.   We have learned over the past few years that we need to do a better job at educating people on what the changes are in order to make the transition as smooth as possible.  The new site tour experience clearly walks people through, step by step, each new aspect of the new Profile.

Here's the official Facebook spot showing off the new design: