(Image via TechCrunch)

Twitter, the hot microblogging service, is set to close a round of financing of around $100 million that values the three-and-a-half-year-old start-up at $1 billion, according to The New York Times.

Twitter’s last round of financing, raised in February, valued the firm at $250 million, meaning Twitter has quadrupled in value in less than a year.

The news of the new valuation was first reported last week by the blog TechCrunch. This morning, details about some of the new investors and the timing were added by the Web site of The Wall Street Journal.

So, faithful readers, is Twitter worth all of the fuss? No one has quite figured out a business model for Twitter yet, but obviously the company is generating a lot of buzz. It was just a few years ago no one could understand why Twitter was getting so much coverage, but now it’s raising money with a billion dollar valuation. Did the early explosion of coverage make that happen? Or was the early coverage simply serving as a predictor that it would eventually happen?