This enables you to add dynamic content (ads, or other promotions) at the beginning and end of your show/
This enables you to content (ads, or other promotions) anywhere in your show (you select where, and the content is inserted)
The dynamic part is you can change the content later and it will update all the episodes that have "Spots."
Dynamic Ad Companies
When I did the research for my book I used a dynamic ad insertion company that put generic ads into my show. It paid .0017 per episode. If you have 2000 downloads that calculates to $3.40 (so these only work for people with HUGE audiences.
Things to Think About
You need to get consistent with your recording volume as you want the dynamic content to be the same volume as the rest of the episode.
You need to think about how you are going to lead into the content and come out of it. You can leave a very small space as when you pick the spot you can go down to millisecond precision.
Don't have "new toy" system and drive away listeners with too many spots.