Blogs can be 'viral'. Say I link to your article about blogs and link to it, first it rank goes up in google, but it means the article has to links on the web. Now someone links to my article about blogs, it spreads. You can't create an ad page on web and get people to link to it for free, but they will do exactly that with a blog.
I would point out that a work colleague watched the teaser trailer 8 months ago. Where? The cinema of course! It seems they are marketing to the people that watch films in the cinema. Pople like me that only go to the cinema on the odd occassion a film comes out I want to watch, missed their clever marketing.
Yes, I did not know it was coming out until I ead it here.