Of all the hundreds of tags you can see in our mashup tag cloud, the second most popular behind "mapping" is "photo". How popular? As of now there are over 200 photo-related mashups listed at ProgammableWeb -- 202 by today's count.
Something new sprang up in the Flickr App Garden last month: "This is my Cam!" by Chris Martin (the San Francisco-based hacker, not that guy from Coldplay). Inspired by music sharing site This Is My Jam and built during Photo Hack Day 3, "This is my Cam!" uses the Flickr API to catalog the different cameras that were used to capture a particular user's photos.