using more data since io6 update

Since the iPhone 4s came out, I've not exceeded 200mb of data in a month. This month I exceeded 2gigs by the 14th. What could be transferring/downloading so much? Do podcasts update over the network now? I know previously it would only get them with wifi. I listen to podcasts every day going to and from work. Is there a possibility that it is streaming the whole time? I don't really do anything else on my phone. No vid sending or games or anything.