Minor nit #1: https://www.dropbox.com/s/2meqa8hhen9ztba/Screenshot%202014-... Seems like the graph visualization is sticking to the wrong coordinates (dragging it to the left doesn't help; it moves back to the center)
Minor nit #2. I'd love to see a visualization of the "probability mixing" interpretation of markov chains and stationary distributions, which is what PageRank is really about. That is, it'd be really nice to have a visualization of the fact that Markov chains are ultimately memoryless (it eventually doesn't matter in which state you start for the distribution of events). I think it could be done by exchanging "probabilities conditioned on the past", which is most easily done by multiplying the entire probability vector by the stochastic matrix and visualizing that.