Piggybacking on the whole Podcasting thing is Photocasting. The idea is sound, in the same vein as RSS feeds, I don’t want to bother checking if you have new photos, why don’t you tell me when you have new photos. So now I have a photostream over RSS.
But, I don’t really think it’s sound. Why? because it works great if I’m adding a couple of pictures each day. What if I add 100 photos all at once? You’ll only see the last 10 or 20 of them. So maybe RSS isn’t the way to go.