"The so-called "new atheist" movement is definitely not so new.
Atheists have been around for decades, and they've been organizing for
decades. But something new, something big, has been happening in
atheism in the last few years -- atheism has become much more visible,
more vocal, more activist, better organized, and more readily
mobilized -- especially online, but increasingly in the flesh as well.
The recent Reason Rally in Washington, DC brought an estimated 20,000
attendees to the National Mall on March 24 -- and that was in the
rain. Twenty thousand atheists trucked in from around the country,
indeed from around the world, and stood in the rain, all day: to
mingle, network, listen to speakers and musicians and comedians, check
out organizations, schmooze, celebrate, and show the world the face of
happy, diverse, energetic, organized atheism.

Atheists are becoming a force to be reckoned with. Atheists are
gaining clout. Atheists are becoming a powerful ally when we're
inspired to take action -- and a powerful opponent when we get treated
like dirt."
http://www.alternet.org/belief/155370/why_atheists_have_become_a_kick...

   Sidenote: I'm nursing a theory about the sudden appearance of
atheism as a cultural force. In reality, I think it was a combination
of three things.

1. A demographic shift. As health and social welfare improved in North
America, while most of the populace headed to the city, the cost of
being an atheist dropped to historic lows.

2. A lack of visible leaders. The last public, outspoken atheist in
American life was Robert Ingersoll, and he kicked the bucket 100 years
ago. Bertrand Russell was a Brit, which reduced his impact on our side
of the pond.

3. 9/11. Because of point one, there was a huge latent interest in non-
religious topics. No one in the media picked up on it because of point
two. 9/11, however, got people thinking publicly about religion, and
helped get Sam Harris a contract with a mainstream publisher. It was
like tossing a match into an old woodworking shop...

HJ Hornbeck