I talked to the opensource.com folk about Mastodon at #ato2017 yesterday. They said the main reason they don't use it is the tools they use to manage their social media presence (mainly Hootsuite) don't have Mastodon integration.
@nivex good. one defining characteristic of what makes Mastodon better than other social media is the relative absence of entities with a "social media presence,," in favor of actual people to talk to.