You need to have a unified experience consistent with your brand so as not to confuse consumers. Your Twitter profile is where people go to quickly discover how you are using Twitter and learn more about your business. Make sure that you get your brand or business messaging across using the 140-character descriptor field.
It is acceptable to tell them how you are going to use this Twitter channel and set expectations. For example, if your account is strictly for distribution of an RSS feed and there will be no human interaction, tell them so. Companies like SUN and Dell have multiple Twitter channels -- each specifically geared to deliver niche content to a target audience.
Tip: Update your Twitter page background with an image that conveys the positioning of the brand. A good example is Dunkin Donuts.

Notice how the company uses a visually branded background, page font, color, and an icon that are all consistent with its brand. Also note that the bio is descriptive, concise, and links to the Dunkin Donuts' homepage.
"Bio: Dunkin' Dave here, tweeting on the behalf of the DD mothership. I'm an American and I'm certifiably running on Dunkin."
