the porn film, 'Shortbus', which was screened at the Toronto International Film Festival
"Shortbus" is not a porn film. Porn movies are all about the sex; any dialogue or plot outside the sex scenes is irrelevant and trivial; and those sex scenes comprise the vast majority of the movie's running time. In contrast, non-porn movies may include some graphic scenes, but they are short and the vast majority of those movies' running time explore nontrivial topics via scenes free of sexual activity.
"Shortbus" is a frank movie about relationships, suicide and depression. Sook-Yin-Lee's character, specifically, cannot understand why she feels unsatisfied by her male partner until, late in the movie, she realizes her true attraction was to women. (This happens to many lesbians.) The most heart-wrenching plot line deals with a man who cannot escape the clutches of depression, depression which creates a shell around him which no emotions can penetrate, most importantly the deep love his partner has for him. A neighbour rescues the man from a suicide attempt.
This is in no way a porn movie. It's a serious movie for and about adults, which contains brief contextual graphic scenes that convey the characters' relationships and emotions.