Here is a quote from a Google Employee responding to the frustration of YouTube users.
Here are a few ways your input has influenced the page's current design...
** YOU SAID:
The "Like" button (which initially not only rated videos, but also saved the video to your Favorites) was confusing. It didn't feel right to rate and add a video to favorites at the same time.
*** HOW YOUR INPUT INFLUENCED THE NEW DESIGN:
By redefining what “Liking” a video means and adding a “save to” button in the actions bar, rating a video ("Liking" it) and saving a video (Favoriting it or adding it to a playlist) are now totally separate actions. So when you want to rate something, use the “Like” button. When you want to Favorite something, use the “save to” button.
This is 2010 and Google still does not employ UX professionals? Who would, who could, possibly think to have one link do two such completely different tasks. Just because you may like a video in the context of general browsing doesn't mean that you want to add it to your playlist.
As an example I may *like* a video of a friends baby but that doesn't mean I want to save it to a site dedicated to Information Architecture.