YouTube will be forcing all of its users to use a new design for their channels (profiles) pretty soon, but 98% of the community doesn't like them, and YouTube doesn't care if we don't. The new designs are simplistic, cluttered, unorganizied, confusing, slow, and they can't be customized to the same extent the old designs can be.
Since they're serious about the switch, at this time, all new members are automatically forced to use the new design.
For a visual aid, compare your profile to an older one (mine for instance if you like) and see the difference in the designs, and you be the judge.