Arbitron & Edison Media Research have released their third annual study on podcasting, and finds that listenership has made another impressive, year-to-year jump. According to their data, 18 percent of Americans listened to a podcast, up from 13 percent in 2007 and 11 percent in 2006. Video podcast consumption was up from 11 percent to 16 percent. Also, nine percent of Americans downloaded and listened to an audio podcast in the past month alone, which adds up to about 23 million people.

The study also found that time spent listening to all forms of online audio for podcast listeners is approximately 90 minutes longer per week than it is for other online audio consumers. Podcast users are also more likely to have a college degree and live in a household earning over $75,000/year. They are also more frequent online shoppers and more Web-savy overall.

The authors of the study conclude that podcasting is a viable alternative means to target attractive consumers who are otherwise proving difficult to reach with traditional advertising. Also, podcasters should consider lifestyles, context and even potential 'dayparting' content to be listened to at specific times for their audiences.

The study can be found here.