[...] There is now a "Reply" button under the audio player on Odeo pages. This way, when you record and share an Odeo with people, they will be able to record a response. (You'll get email notifications of this activity so you can keep up with the conversation.)
I definitely want to see how Shel and I can implement this feature for For Immediate Release. Our podcast is listed with Odeo so you can also subscribe to it there. We've already added an instant-play feature to the podcast blog (just click to listen to a show); if we can also provide a way for listeners to easily make an audio comment there and then, while the impulse to do so is hot, that would be terrific.
Now if iTunes had a feature like this...
Odeo has also introduced a rather neat audio messaging service where you can record a message and send it to someone. And you don't need to have an account with Odeo to use this service.
Do give it a try!