Google started testing audio ads back in December 2006. In May 2007, they launched it to the masses and we saw some early feedback on those ads.
But yesterday, we got news that Google will discontinue those ads and will likely fire the team of 40 people in that group.
Since the announcement, we saw at least two sad advertisers. In two Google AdWords Help Threads we saw complaints that Google dropped the program.
In fact, one person noticed something was wrong before the announcement when he said that he wasn't receiving any estimates from stations anymore. A Google representative was just as surprised to hear the news, saying:
Yes - I just learned of this today, myself. I would want Kathy to note, though, that ads will continue to run through the end of May.
It is sad to see things fail, but Google should focus on what they do best.
Forum discussion at Google AdWords Help Threads.