A picture of thousands of words

Late last year I posted a graph of this blog here. The java applet to create these graphs is to be found here. There is something strangely fascinating in watching the graphic form. I am not tecchie enough to understand what the different elements represent and now I am puzzled that, although The Last Ditch now contains hundreds more posts and many hundred more links than it did last year, today's graph appears simpler. Can any tech-minded reader explain why?