[An aside about exogenous social capital: you might complain that your tweets are more interesting and grammatical than those of, say, Donald Trump (you're probably right!). Or that your photos are better composed and more interesting at a deep level of photographic craft than those of Kim Kardashian. The difference is, they bring a massive supply of exogenous pre-existing social capital from another status game, the fame game, to every table, and some forms of social capital transfer quite well across platforms. Generalized fame is one of them. More specific forms of fame or talent might not retain their value as easily: you might follow Paul Krugman on Twitter, for example, but not have any interest in his Instagram account. I don't know if he has one, but I probably wouldn't follow it if he did, sorry Paul, it’s nothing personal.]
In publishing circles, this has long been known as platform or author platform--ie that thing that made you famous in the first place that gives you the space to attempt to try to use that fame to sell books.