The whole 'sell before you build' theme is plastered all over this thread, as I expected. I think this originates from the whole lean/MVP school of thought but is sold in threads like these as though you can just create a 'coming soon' page with email sign up, wait for 1000 emails and then write your first line of code. In reality it is about building only what's necessary for a minimum viable product then ship and only add features which are demanded of you (i.e. adding value not speculating and building stuff no-one cares about). This does require some work/thought/assumptions up-front. It's not as easy as people make it out to be!