Free is always the spirit of the internet, but when starting a startup...I was told to spend as much time on my business plan (revenue), as I would coding.<p>When any website or app begins charging, or throwing ads out, there's always an outcry from the users that weren't use to it. Sure being free will probably make any startup grow faster, but to make your users happy...charge, have ads, or AT THE LEAST tell them that you plan to charge later, or aim for acquisition like Instagram :)