Using a portable player, such as the iPod or a cell phone, podcasts are instantly available and can be listened to progressively while tending to other matters, therefore educating a busy listener at no time expense.

From the producer's perspective, podcasts cannot have live participation or immediately reach large audiences as quickly as radio can. However, podcasting allows individuals to easily transmit content worldwide without the need for expensive equipment or licenses, and is frequently used together with an online interactive bulletin board or blog.

(Source: wikipedia.org)