photo sizes 1
Striatic raised an interesting question in Utata: do people prefer horizontal or vertical shots? What is the ratio? Here's an analysis...
So I considered the latest 1000 photos from Utata, obtained their width and height via the API, and calculated the log of the width/height ratio. That's the blue graph. There's a clear preference for horizontal photos, and there are spikes for the 4:3, 3:2 and 1:1 ratios.
Then I did the same for FlickrCentral (red graph). The graph looks almost the same, except the spikes look reversed. FlickrCentral has more 4:3 photos, Utata has more 3:2. There are less square-format photos in FlickrCentral than there are in Utata (out of one thousand, of course).