Yet last week the company received an investment of an undisclosed amount from Union Square Ventures. Twitter has also received funding from Obivious Corporation and angel invenstors such as Marc Andreesen.
USV admits it has no business plan for Twitter. Its investors are feeding money to build a robust platform, and they'll figure how how to make it pay as they go. That's par for the course for a lot of Web 2.0 startups, and USV's investment is validated by other examples of Web properties that draw crowds (and sometimes massive payouts) by enabling user-generated communication (think Flickr and YouTube).
USV touts Twitter as an emerging form of communication that takes the best elements of blogging (a form of public communication that doesn't necessarily require a response) and adds the immediacy of banter that you'd get from a live conversation.
To my mind these are the worst features of Twitter. Thanks to spam and an infinite supply of inane blogs, the Internet's signal-to-noise ratio is already dangerously out of whack. Twitter's emphasis on immediacy simply ramps up the injection rate of crap into the communication stream.