This week, Facebook will be phasing out its old layout in favor of the "New Facebook."
The new site features tabbed browsing for applications as well as a new look for profile and home pages.
Before this week, users were able to choose which version of the site to use and were able to share comments about the new layout.
Due to the high volume of users trying out - and sticking with - the new site, Facebook will be phasing out the old layout and users will have to use the new version.
