I've been following Nxt for a little while, although it's hard to keep up with this thread!  This is my first post.

I've seen several questions and efforts at characterizing aspects of the blockchain.  I've been doing some exploratory analysis and have several plots to share.  I've posted what I've done so far here:

http://brosephus.github.io/nxt-explore/

I've learned a lot and hope this might be useful for others.  I'm happy to look into anything that might be of interest to anyone.