John Dennis started his podcast Smart Time Online. Little did he know that by putting his best advice into audio form, it would gain so much interest. He would get past gate keepers and end up getting contracts with BIG companies. The problem then became continuing his podcast. As John puts it, "Because of my podcast I had to quit my podcast to take care of my customers." It still brings him leads and potential customers even though he hasn't put out an episode in a while.
He is also the moderator of the Podcaster's hangout Facebook group (the largest Facebook Group Devoted to Podcasting)