Especially when you consider how Google+ got millions of users quickly and how Formspring.me was once described as "addictive". The only thing left is figure out how to be more entertaining than the competition and not get boring. Formspring.me loses its novelty value after a while.
However, I believe you are a minority. Few people think about creating something popular with the mass market. Most seem to want to build a "niche" product so they can buy their McMansion in the suburbs. Most people want to be engineers or entertainers, but not both.
Steve Case used to tell AOL employees, "What can you do for AOL that will get people to ignore Seinfeld after dinner and head straight for AOL?" https://www.google.com/search?q=steve+case+%22would+always+s...
However, I believe you are a minority. Few people think about creating something popular with the mass market. Most seem to want to build a "niche" product so they can buy their McMansion in the suburbs. Most people want to be engineers or entertainers, but not both.