Is Twitter really worth anything to a business user?

Monster Blog has an important explanation as to "How Twitter Can Help Your Career".

While A-blogger Dave Winer also writes an explanation about Twitter in "What Twitter Is".

Basic idea for business users - stitch together the diverse blog post you make in a day, or any other article, comment you make online. Simply add a single line of text and a link and stitch together a summary of what you do in a day.

Dave Winer says about Twitter:

So what do all these parts add up to? Users and relationships between users, their ideas, and an ecosystem. It's probably the basis for some pretty hot apps. Will it be possible to monetize them? Without a doubt. People who say that Twitter hasn't figured out how to make money don't understand the role technology companies play in the much larger media and communication ecosystem. Ideas gestate here, grow up, find users, and then find customers. In a way Twitter is a mega-enterprise product, and by using it, we're helping them prove it. Their customer is likely to be a telco or an entertainment network. But it's way too early to cash it out, they all took the right approach, seed it with some more capital to add more bandwidth, solidify the back-end, add a bit more functionality, and wait to see what the users and developers do with it.

Twitter is a good place to summarize what you do in a day. Think of it as marketing yourself through linking what you do.