If you record it, they will come...

At least, if you're recording podcasts. A new study by eMarketer has found that the U.S. podcast audience rose to 18.5 million in 2007. It is expected to hit 28 million by the end of this year and 65 million by 2012.

Where the eyeballs -- or ears, in this case -- go, the dollars will follow. eMarketer sees podcast-related advertising in the U.S. more than doubling to $435 million by 2012.

A number of factors are driving the growth of the podcast-user base:

* Greater ease of consumption for podcast content
* Growing awareness of podcasting
* Terrestrial radio’s use and promotion of podcasting
* Increased penetration of portable players
* The evolution of smart phones and proliferation of affordable mobile data plans

Just a quick note to mention that I'll be speaking at the Social Media 2007 conference in Chicago this week.

My topic: How To Pod-ergize Your PR! I'll be presenting on Friday afternoon.

I spoke at this event in Atlanta in January, and can say that for any organization interested in getting into blogging and/or podcasting it should be quite useful. I'll try to do a blog post or podcast episode based on new ideas from the conference once I get back.

Podcasting just got another big boost ... this time, from the auto industry.

Apple announced today that it has partnered with GM, Ford and Mazda to make iPods compatible with their car stereo systems. I'd be happy to have such functionality myself, making podcasts an even better drive-time companion.

Here's what Apple had to say in its press release:

"We're delighted that Ford, General Motors and Mazda will support iPod connectivity in nearly all of their new models," said Greg Joswiak, Apple's vice president of Worldwide iPod Product Marketing. "Now more than 70 percent of 2007-model US automobiles will offer iPod integration, with General Motors alone making it available on all 56 of its models, representing millions of cars and trucks."

Podcasting is clearly catching on.

A new report from Nielsen/NetRatings finds that 6.6% of all U.S. adults online have recently downloaded an audio podcast. This equates to 9.2 million podcast listeners.

For comparison, this figure surpasses those who publish blogs (4.8% of the U.S. adult online population) and online daters (3.9%).

Further, 4.0% -- or 5.6 million Web users -- were found to have recently downloaded a video podcast.

"We can expect to see podcasting become increasingly popular as portable content media players proliferate," Michael Lanz, an analyst at Nielsen/NetRatings, said in a news release announcing the findings.