Reputation and brand matter a lot in business these days. People are quick to judge you on the basis of your reputation and online presence before making any decision related to business, including business deals and investments.
A CEO acts as the face of a business and company. Therefore, the reputation of a CEO is closely linked with that of a company. CEOs these days are under constant pressure and are scrutinized for their online presence. High usage of social media for multiple purposes is also a reason for that.