I guess the MPAA announced that they will include a brief explanation of why the movie received its rating. Haven't they already been doing this? I guess now it will be more public? In some cases the brief explanations don't help at all. I remember a list saying X-Men 3 had drug use. I think there is a difference between smoking a bong and a made up drug that eliminates your mutant power. Anyways, take a look at this article, or rather just watch the commercial in it.
You're right, they have been doing it. Maybe they are just promoting it. When I worked at a theater it was very rare for someone to ask for a rating's reason. I probably had just as many parents upset that they could not just buy a rated-R movie ticket for their kid.
But with the popularity of the internet, there are better explanations out there. IMDB actually has a really good parental guide for movies that is crowd-sourced by users and gives more detailed information so you know the difference between "drug use" meaning a bong or mutant elixir.
I liked the video too. Good way to convey their message. However I thought using a Teddy Bear to represent "Rated G" was a terrible idea. I don't think very many people think of Teddy Bears as being G Rated anymore.