I think that a company's social media interactions are extremely important. When a company or organization tweets, everyone can see it. In fact, Twitter is one of the best ways that a company/organization can build rapport with future customers and clientele.
Therefore, delegating social media relations to an outside or "ghost" source is unwise. Corporate Twitter accounts should be taken very seriously, and generated in-house. This way, companies can have more control over what they are tweeting, and they can take responsibility for their tweets. Social media posts are a reflection of a company's image. Managing this image should be a top priority.