While it is not immediately clear whether or not YouTube will be pursuing longer subject films in addition to short subject ones, it is safe to assume that they are looking in that direction. Their blog post says that, "Today, we're pleased to announce the launch of the YouTube Screening Room, a platform for films from around the world to find the audiences they deserve." Given this statement, it does not appear that the site will be limited to short films.
The YouTube Screening Room could give a great break to films that were not able to find a solid audience or were not even released to the public in the first place. Other than the obvious benefit of exposure, monetary benefits to those who are making these films have not been publicly discussed by YouTube.
The videos include a "Buy Now" button, which, in some cases, directs you to the website of the filmmaker/film and in others links to a place where you can buy a DVD or digital copy. Some of the links don't exactly point to the right place yet and it's a little unclear to me why people would want to buy a short film that they just watched for free online (aside from upgraded quality), but I'm sure the kinks will get worked out. The purchasing model might work better if and when they offer feature length films.
Being a cinephile, I am excited to see the sort of films that come out of this new venture. They are off to a good start already with the four short films that they already have. YouTube Screening Room could prove to be a much needed boost to the indie film community.