First off, they aren’t interns
The common trope of the social media manager is that they’re interns fresh out of college who need to teach others what’s up online. That’s not the case. They’re strategists, copywriters, art directors, analysts, account managers, project managers, content creators, publishers, and team players.
Many brands Tweet multiple times per week — if not per day. A social media manager looks at what gets posted, when, and for what purpose. They look at how those posts perform, if they measure up to benchmarks, and tweak the course to meet business objectives. A good social media manager knows how to connect with and engage an audience, especially on a highly-engaging platform like Twitter.