The popularity of any product or service whether it is digital or not really depends on the fact that is the product even creating value for its consumers or users. If the product or service is not creating value and not providing anything useful to its users or consumers then it is highly likely to not get popular. When you make website like Instagram you are basically providing people or users with the opportunity to create strong networks and build strong relationships with people that will come in handy in your professional careers and in your personal lives. What other reasons might be there?