If you listen to any of the top podcasts, you will likely find they have a definitive brand identity. Most will have Idents or jingles at the beginning and end to let the listener know what they're listening to. Idents consist of a short piece of music, usually teamed with voice-over or effects to identify the podcast. These help to make your podcast sound professional and also build up familiarity with your listeners. Idents are either written specifically for a production, or purchased as stock music from libraries such as www.beatsuite.com.