The simple answer is that you redefine mainstream. Mainstream doesn't mean that everyone uses it like Facebook, but instead that "everyone" uses it just like "e

The simple answer is that you redefine mainstream. Mainstream doesn't mean that everyone uses it like Facebook, but instead that "everyone" uses it just like "everyone" uses shopify or github. Quora goes mainstream when a certain elite, much like the Salons of Paris, gather there. Academics, Business, Cultural, Medical, Scientific and Technology elite all show up.