"Advertising is a tax for having an unremarkable product", said someone (http://thebrandbuilder.wordpress.com/2008/11/12/is-advertisi...)

Or in other words, spend your time and money not on advertising, but on making a product so compelling that your users/customers advertise for you. Think Dropbox, Instagram, Facebook, Twitter, Skype – no advertising, but a product that people will encourage others to use.