Twitter is currently developing a new “Contributors” system that will allow multiple users to post to the same Twitter account. Mashable has the screenshots and details about the upcoming feature, and the API developer mailing list has info about the new API calls.
Ordinary users won’t see much different, aside from the fact that Tweets from contributors will have a little callout (e.g. “by Evan Williams”) next to the timestamp and source. Where things get interesting is for contributors, and those running allowing contributions.
If you have the Contributors feature active, you can give another Twitter user permission to update the status of the account. Two access levels allow you to decide whether you want the user to simply be able to post updates, or to be able to access the dashboard.
Contributors get a small “toolbar” along the top of pages on Twitter.com that allows them to switch between their own account and any other account they have permission to update.
The feature isn’t being rolled-out yet, but many speculate that it’s phase one of Twitter’s revenue model. It sounds like a feature that would especially appeal to corporate customers, as they might want to enable several employees to post updates to their Twitter presence. It goes right along with my predictions that Twitter’s business plans are to sell analytics (such as retweet statistics, what with the new “project retweet,” especially) and to provide extra features, such as account sharing and an easy way to keep tabs on trends involving their brand, to businesses.