[Whitehouse.gov petitions are] probably even less effective. I've yet to hear of any sort of legislation come about as a result of one of these.
+1. Moreover, some recent petitions border on parody of the entire concept.
Given the recent trend towards movie theater shooting rampages, perhaps it would be more productive to petition the WH to enact a "Movie Theater Violence Prevention Act" consisting of a prohibition on future movie adaptations of comic books and Stephanie Meyer novels. I, for one, would give such a measure my full support.