Could you please explain this? I have never heard of it.
Tor (The Onion Routing,
http://torproject.org) is decentralized anonymizing network. When you install it's client (there are Vidalia bundles for all major platforms containing Tor client, Polipo http proxy, Vidalia control center and TorButton, extension for Firefox), you can browse Internet anonymously (as far as you are following some basic security rules.
Yesterday I created "Tor hidden service", which is exposing my pool as anonymous server in Tor network. When you're using
http://lcir2ce5utha5xoo.onion:8332 for your miners, then:
a) Service provider (me) don't know your IP
b) Your ISP don't know that you're accessing pool
c) You don't know where's that service located (however this is not true, because pool is accessible also thru normal IP address).
You may be interested in point a); while creating anonymous account on the pool, you can mine completely anonymous coins. Even I don't know who you're, except your login and payout address. Unfortunately routing miners thru Tor network will lead in much more stale shares, because Tor network is sometimes pretty unstable and laggy. It may be better when LP&Ntime rolling will work over Tor, but don't expect <1% stale rate now.
I'm interested in the fact, that Tor network have around 3000 relays worldwide (
torstatus.blutmagie.de), so exposing pool directly as Tor service is like to have hundreds of entry points to the pool; it's hard to shut down all of them at same time ;-).
This testing of Tor hidden service is just a part of bigger picture of fighting against DoS. Currently the hidden service endpoint is the same balancer as public one, so null routing of this IP will shut down hidden service as well. But some things are moving on...
Tor article on Wikipedia