I like the graph myself (it was snagged from someone's flickr account according to the credits). The second section does show the average salaries for various positions in and out of the Valley, and the third position shows that those Valley salaries don't even remotely start to compensate for the higher cost of living there, which means that Valley salaries are not only not really competitive at all, but are underpaid by a considerable margin. Cool graph for showing that.