It's a brilliant strategy, isn't it? User acquisition costs for a product like Dropbox can be fairly significant, especially if you're going toe-to-toe with ev

It's a brilliant strategy, isn't it? User acquisition costs for a product like Dropbox can be fairly significant, especially if you're going toe-to-toe with everybody else in Google. On the other hand, a gig of storage borders on free for Dropbox, but the marginal utility of that storage is pretty significant for the user, providing a strong motivation to actively recommend (an admittedly excellent) service to their friends. You get more storage for 'free', Dropbox saves a bucket of money on advertising. It's genius.