To be fair, its different for every product. If you aren't a social network, I don't see how you could go viral. Search ads wont work if nobody searches for y

To be fair, its different for every product. If you aren't a social network, I don't see how you could go viral. Search ads wont work if nobody searches for your product, ie if it is something completely new. You can't get users to refer friends if you have no incentive to give. This is why I pay closer attention to advice that is descriptive, rather than prescriptive. Tell me what your situation is, and what you did that worked, and let me extrapolate. Bonus points for what didn't work.