From the NYTimes earlier this week:
The study, which polled 2,210 people and was released this fall, found that the increase in blog readership from 2004 to 2008 was 300 percent; 47 percent of online consumers now read blogs.
Half of blog readers said blogs were useful when they were considering what purchases to make, and more than half of that group said they looked at a blog just when they were about to buy something.
“This is what people are trusting more and more,” said Valerie Combs, vice president for communications at BuzzLogic, a company that analyzes social media and operates an Internet advertising network and that commissioned the study from Jupiter Research. “What we’re seeing online, increasingly, is that people are relying on peer opinion.”