Writing Short - the new way forward?

I've noticed that many books are now rather, um, brief. I just read a delightful book of 150 pages, of which about 40 pages were pictures, or one sentence quotations taking up one page, and other such things.

The book itself was excellent - but short.  In this case it made its points well, but the larger question is…. are we becoming a culture that simply can't deal with long books — unless they are about vampires?

The Huffington Post asks for 200 words or less.  Twitter allows only 140...