He wrote it after his wrap party for his next film, his low-budget horror piece Red State, and as he's his own editor he edited the film as he shot it and had a nearly-complete cut of the film, which he showed at said wrap party. He also talks in the entry about the DIY quality of the shoot, which will extend to the film's ad campaign. It's why the film already has a teaser poster.
Anyway, I'm rambling and if I try to sum up the entry, I'll write something longer than the entry. Try reading it.