What you're looking at (in the banner) is a word cloud (I made 4, actually). You can create a word cloud by drawing up a list of words and then using either wordle or wordcram to create an image. My clouds are based on a list of words drawn from the topic of ebooks.
I like the idea, but I'm not entirely sold on how I'm using it. What do you think?
P.S. If you're seeing a dog but (and not a word cloud) it's because that is the one banner I haven't replaced yet.