If you have podcasts in iTunes, an exclamation point may appear to the left of a podcast or podcast episode in certain circumstances.
This can happen for several reasons:
iTunes has stopped updating this podcast because you have not listened to any episodes recently. Would you like to resume updating this podcast?You can click Yes to continue downloading additional episodes. Or you can just listen to any part of any episode and a new episode will download at the next update.
Note that with iTunes 4.9, you cannot edit a podcast address. If you typed the address in manually (as opposed to subscribing from the iTunes Store), you will need to delete the podcast subscription and resubscribe with a valid address.