Success is above all determined by the execution of the idea as well as its marketing. And even with brilliant execution and a fantastic marketing strategy, mo

Success is above all determined by the execution of the idea as well as its marketing. And even with brilliant execution and a fantastic marketing strategy, most things are still doomed to fail. Luck still plays a brutal and major part - the internet is chock full of successful startups/sites/projects that lingered in obscurity for many months or years without catching on, and then suddenly blew up and started to go viral without any particularly clever action on the part of the founders. The important thing is to resist the urge to explain success and failure as if they are deterministic when they're really driven by essentially random factors (to be precise: they're not random, but they're so unpredictable and difficult to control that to us they might as well be). The "execution is everything" mantra is true for most types of products, and poor execution can explain failure, but IMO it's far overrated for things that rely on virality. Even if you do absolutely everything right, there's always a significant chance that an inferior me-too ripoff is going to be the one that gets all "your" users. Which is why it's so much smarter to build things like Breakup/Crush Notifier as weekend projects rather than startups.