In addition, by 2012, more than 145 million people, or 67 percent of U.S. online users, will be reading blogs at least on a monthly basis. The ratio increases from a readership of 94 million in 2007, or 50 percent of Internet users, the study states.

"Once a haven for techies to communicate with each other in their own lingo, blogs have long since shed this mantle and tapped into the zeitgeist of American culture," according to Paul Verna, eMarketer senior analyst and author of the new report. "There are blogs for virtually everything under the sun, from celebrity gossip to political commentary to the most mundane personal minutiae."

Verna also pointed out that blogs are turning into a big business.

"Buoyed by these massive levels of consumer engagement, U.S. blog advertising will reach $746 million in 2012, up from $283 million in 2007," said Verna, according to eMarketer. "A big factor driving the increases is the niche orientation of the blogosphere.”

Just like podcasts, blogs tend to appeal to specific audiences. Accordingly, much of the demographic targeting which marketers work so hard in the mainstream media is already done for them, according to eMarketer. "Furthermore, the rates at which blog readers notice and click on ads suggest that they are a well-primed audience," he added.