YouTube’s path from a loose, rowdy, anything-goes video destination to a more well-organized and advertiser-friendly Web site took a giant step Thursday with the addition of TV shows and movies, courtesy of new deals with Hollywood studios. That step could actually be considered a light-years leap for YouTube, which just two years ago was fending off legal actions from major entertainment conglomerates complaining of user uploads of copyrighted material. Now, the new “Shows” and “Movies” section of YouTube has analysts talking about boosted ad revenues.