Tom and Mike,
this looks like a very solid piece of work (software, tech report etc)!
The installation is very very easy, and worked just fine on my ubuntu-eee.
This has the potential to be ground breaking and lead to massive adoption of large-scale
darknets.
I guess your 3 biggest challenges towards adoption are:
a) discovering content; b) performance issue due to friend-forwarding and
c) usability issues as users are not very familiar with public keys etc. still
you've been tackling this quite well.
Just wanted to say some nice words, perhaps I will come up with something useful
and insightful at another time :)