Free i pod content?

i pod cast is more like your audio diary as well as a radio program. you might creat it regularly and it will be sent to the listeners who signed up as the creator's subscriber. so it is the same mechanism as japanese SMS, mixi's diary because friends on the list can read the diary whenever he or she uploads a new diary.
i pod cast can be about anything from sports to education.however, one thing i did not understand was, it said "beyond porno", but does not i pod have any regulation? can everybody really talk about offensive things on ipod cast like violent or sexual contents? does FCC or other organazation let them speak or put contents that might offend people?