This is interesting, but I think it speaks more to which "beachheads" companies are choosing rather than which markets they ultimately target. For example, with consumer vs. enterprise I suspect that when Dropbox did Demo Day they would have been labelled a "consumer" company although the enterprise potential was obviously there. Vertical SaaS is another example--choosing a vertical is an excellent way to start, and it can be enormously lucrative for a small team, but I imagine that "VC-style" exits will usually require branching past it.
Nice analysis, but it's hard to draw conclusions from only two data points. Seems like you have the data for up to 12 demo days and it would be really cool to have someone make some graphs (though maybe this was already done and they were intentionally withheld ;) ).
For those wanting to dig further, here's a list of all companies (active/exited/dead): <a href="http://yclist.com/" rel="nofollow">http://yclist.com/</a>
What's the end game for a YC non-profit? Besides corporate social responsibility, how does a non-profit founded at YC benefit the business ecosystem at large?