Over the last few days, Facebook has apparently been rolling out some UI changes to a small number of users, moving many of the navigation elements that currently rest at the bottom of the screen back to the left sidebar. The changes are subtle enough that they probably won't spark yet another user rebellion against Facebook — aside from the people who will hate it automatically — but they're very significant. The changes in the screenshot above are nearly identical to the shots that were presented at Facebook's developer garage a month ago. But there are some key differences. First, search now has much more prominent placement, appearing just above (and almost as an extension of) your News Feed.