Bridge Ratings estimates that 4.8 mln Internet users have at some time during 2005 downloaded a podcast from either a radio station or other source. iTunes was referrenced as the most often accessed portal for podcast downloads. This 4.8 mln estimate is up from 820,000 podcast users in 2004. By 2010 podcast audience growth is expected to reach a conservative 45 mln users who will have ever listened to a podcast. Aggressive estimates place this number closer to 75 mln by this date.