Awareness of podcasting has risen considerably over the last year - from 22 per cent in 2006 to 37 per cent in 2007. However, the number of people listening to the format remains relatively static, up just two per cent to 13 per cent, over the same period.

That's the headline results of a new poll by Edison Media Research released last week. The poll was based on 1,855 telephone interviews which took place in January 2007.

Even worse is the news for newer formats: the number of people who had ever watched a video podcast rose only one per cent to 11 per cent.

When it comes to the content of podcasts, the most popular category is technical news and commentary, followed by national and local news, which had equal interest for listeners. The least popular category of podcast was 'interviews with celebrities', which was rated not-at-all interesting to 70 per cent of listeners.

Podcasts are not restricted to or favoured by a particular demographic when it comes to age or sex. There are just two per cent more men listening to the format than women; and while 18-24 year-olds make up 11 per cent of the audience, people over the age of 55 make up another 12 per cent.

On the other hand, podcast consumers are likely to be well-educated and to live in higher income households, likely to own an HDTV and some sort of DVR device, as well as, of course, an iPod or other portable media player. They spend more than five hours longer on the Internet each week than non-consumers and sixty per cent of them read blogs, though they are unlikely to have their own. They are almost four times more likely to have purchased MP3s or other digital audio than those who did not listen to podcasts.

As you might expect, podcast consumers are more likely than most to use DVD subscription services and they are twice as likely as average to own a videogame system of some kind. They're also more likely to be online shoppers. While 58 per cent of the non-listeners had bought online, this rose to 79 per cent among podcast consumers.

Almost half of podcasts - 46 per cent - are consumed at the computer. This is even more true for video podcasts, where only 27 per cent view the format on mobile devices, presumably reflecting the relatively recent invention and higher cost of such players.

Finally, while podcast audiences may seem to be an attractive audience for marketers, they are also more resistant to unwelcome advertising. On average they were 15 per cent more likely than non-listeners to use software that blocks spam, pop-ups, spyware and banner advertising.