wtf is this youtube url about?? ive never seen it before!!

i went to youtube com as you do and the url got switched to:
youtube com/?noredirect=1
i thought that was weird :S but i logged in after i logged in it went back to:
youtube com/ ?noredirect=1

any ideas why?? or what this redirect is about?? :S could it be the enhance views plugin i got ?? :S