Why not expand this proposal to other anonymizing networks - Freenet, I2P, and others?
I'm concerned that including other anonymizing networks, such as Freenet and I2P, will make the site too broad. As it is, the site would include Tor and any solution which use Tor in some way, such as Orbot, Orweb, and Tails.
Besides Runa'S answer I'm sure that a site about anonymity networks will attract mostly Tor questions. At some point people who are interested in other solutions will leave the place and in the long term questions which are not about Tor remain unanswered. From my point of view it might be a good idea to have a Tor specific site (like proposed) and a site which covers other anonymity networks. It is a bit like AskUbuntu and Unix & Linux SE.
For the separate overlay networks (darknet) such as I2P, Freenet and so on, there is now separate site Deep Web, this went private beta few days ago.
My interest in this StackExchange site is solely for the agenda of promoting the proper use of Tor around the world, ideally for the preservation of privacy. I don't really want to participate in a StackExchange that takes a shotgun approach to Internet privacy, occasionally discussing Tor but also a great number of other technologies. It all comes down to signal:noise ratio. I very much like the narrow focus on one privacy tool that, when you really dig into it, offers a very rich substrate for broad and deep discussion,