Every once in a while, when the audience is expecting to see one thing, you have to show them something else.
As a footballer I can't imagine life without the use of one of my legs... Sadly this is exactly what happens to thousands of children every year when they accidentally step on a landmine.
When a company is charging money for a product - as Evernote does for all above its most basic service, and same for Dropbox and SugarSync - you understand its incentive for sticking with that product.