Everything you need to know about using Twitter for marketing and PR is at this very descriptive url:

http://www.howtousetwitterformarketingandpr.com/

That’s right: Don’t. Don’t use Twitter for marketing.

Why?

Let me draw a comparison for you: What would you call someone who uses a program to automatically send you an annoying volume of email? A spammer. So what makes you think that because it’s 140 characters and on some trendy web service that blasting away with soulless and automatic links isn’t spam?

So that’s why I say automated means to add content ...