Back in December, Twitter noted a new feature it was testing out, Contributors. Basically, this allows multiple people to tweet from one account (with individual attribution below the tweet). Twitter noted that the feature wasn’t quite ready for prime time yet, but they started using it on their @twitter account. Today, the service has started rolling out to others.
The Salesforce account had the feature turned on about an hour ago. As you can see, they’re already using it.
Contributors is thought to be a part of Twitter’s plan to give premium features to businesses. Though they’re apparently not charging yet for it, one could envision when their business tools are ready to go, this would be wrapped into it.