Thing is, there's so much more on the Internets now than in 2008, people have so many more choices of where to go.
The internet used to be silos of information (site pages, blogs and forums) from one domain to the next, but things have changed dramatically in the past 5 years. The web tools available have turned the internet into matrices of information (the cross-referencing and integration of topics, sites, users, etc). While blogs and forums still exist, I think forums will continue to shrink until they serve only a core audience that eschews change or highly specialized audiences such as product support, blocked content (ie porn) or topics where the web interests of the users are quite narrow, maybe people who are Jeep fanatics or NFL fans. Atheism, or any topic on religion, is not sufficiently specialized to allow a forum to grow, and it's too generic to resist the cross-referencing of the internet tools at hand.
Given the decrease of installations of forum software, any community will have to change to fit the tools of the day. Some of these tools, like Facebook and Google+, make it plain that they do not want anonymity (though it can be forced if required), and consequently some of the things discussed on those sites are limited due to that lack of anonymity.
There are older incarnations of tools that people used to gather and share, such as Google Groups:https://groups.google.com/forum/#
However, since Google is pushing Google+ and since Google+ has Communities
which are intended to replace Google Groups at some point, what is the point of creating or continuing in a Google Group if Communities are the way to go?https://plus.google.com/u/0/communities/117800767173909228802
Nevertheless, we do have representation on both Google incarnations of communities
. These have not been used because the forum has continued to work, but we also complain that we aren't getting enough hits, memberships, visitor emails, etc. As HAL said, one of these days Brain is just going to give up on this domain. I don't think Sam Harris expected Brain to keep it open forever just because it was referenced in Harris' book, and more over, Harris referenced the book not the forum. If there wasn't a book titled WWGHA with YouTube videos uploaded in the early days of that popular site, this forum would look like a desert. Brain happened to capitalize on the right tools for the time; those tools have not matured and morphed along with the rest of the web.
This is why I have suggested that we find another place to go when this place goes to hell and never comes back. Creating another domain and installing forum software and expecting people to populate it will be like throwing money and time down a hole.
If the other alternatives are not for you, certainly that's your choice to go and do things elsewhere. If the other alternatives do not provide the possibility of creating communities, then perhaps your time on the web has passed. The web gurus have decided that this is the way to go.