It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

×
And I mean "peer 2 peer".

http://www.rockpapershotgun.com/2012/07/18/runic-explains-why-torchlight-iis-taking-a-while/

In this article, mention is made in a couple of places of what to do when clients lose connection to each other. Does that mean that multiplayer will be peer 2 peer, instead of going through a server (player hosted or otherwise)?
Multiple responses on this thread says that yes, it is P2P. I didn't find enough time to find an official statement, but I'm guessing the people on their forums agreeing like that is a strong indication.

http://forums.runicgames.com/viewtopic.php?f=30&t=30221&p=268299&hilit=peer#p268299
Ah cool, thanks!
And this makes it a superior product to one with a central server.

Now if only they'd scrap the DRM.