O sinner! Consider the fearful danger you are in: It is a great furnace of wrath, a wide and bottomless pit, full of the fire of wrath, that you are held over in the hand of that God.

American faith has gone through many awakenings. Depending on how you count, there have been three or four distinctive surges of Protestant religiosity in the United States, marked by tent revivals, missionary work, widespread conversions, and, often, intense rhetoric about the consequences of sin. These "Great Awakenings" have been memorialized through texts like "Sinners in the Hands of an Angry God," a sermon delivered by the preacher Jonathan Edwards in 1741, who warned of the "fire of wrath" in hell.

So it's provocative to title your book Atheist Awakening. Oxford University Press's newest release on non-belief, by researchers Richard Cimino and Christopher Smith, claims to be the "first sociological exploration of organized secularism in America," tracing the evolution of the atheist community over the past several decades. The "awakening" part is "not so much a growth in numbers as an awakening to claiming atheism for themselves, and becoming more public about it," said Cimino.

By numbers alone, American atheists really aren't that big of a group. According to a 2012 Pew report, atheists make up only about 2.4 percent of the population. Even agnostics, whom you could maybe call atheistic-ish, only account for an estimated  3.3 percent of Americans. Although both groups have grown somewhat since 2007, the bigger change has been among those who identify as "nothing in particular"—roughly 13.9 percent of the population, which is an increase of 2.3 percentage points over five years.

When you read headlines about the rise of the so-called "nones," or people who don't consider themselves part of a religion, that's what they're mostly referring to: the shruggers. They might be intensely spiritual or perfectly apathetic about faith, but for some reason or another, they don't self-identify as definitively atheistic.

Among those who do identify as atheists, though, the tone taken toward organized religion, especially recently, has been more shout-y than shrug-y. At the 2012 Reason Rally in Washington, D.C., for example, "a band fired up the crowd with a rousing song that lampooned the belief in 'Jesus coming again,' mixing it with sexual innuendo," Cimino and Smith write. Attendees sported T-Shirts and signs with slogans like "I prefer facts" and "religion is like a penis" (involving a rather extended metaphor). There was a life-sized Jesus puppet.

This wasn't just some small enclave meeting for some drinks and Judeo-Christian trash talk; there were between 8,000 and 20,000 people there (a puzzlingly wide range of estimates, but still: in the thousands). Richard Dawkins, one of the keynote speakers, encouraged attendees to "ridicule" people's faith. Not all atheists take this tone toward faith, but it's a somewhat common posture, especially among some of atheism's most vocal advocates, including Dawkins and people like PZ Myers and Bill Maher.

"It's definitely one of their strategies," said Cimino. "There is this strong attempt to be kind of irreverent." This is a quality particular to "new atheism," he said, a term for Dawkins-style arguments against faith, which rely heavily on science and invocations of rationalism. "There's a sense that once you make fun of it, you can kind of demystify religion," he added.

But there's also a sense, at least in reading Atheist Awakening, that derision toward faith among outspoken atheists is partially a product of accumulated bitterness. "It is hard not to come to the conclusion that atheists have spent a far greater deal of time thinking and writing about religion than religious people ever have of atheists as a group," the authors write. American voters disapprove of atheist politicians; parents dread the possibility of atheist boyfriends and girlfriends for their kids; and in general, the public feels less warmly toward non-believers than almost any other faith. Being an atheist means defining oneself in opposition to theism, but that doesn't necessarily go both ways. America is a land of ambient distrust of people who don't believe in God, but mostly in the way of a high school full of queen-bee cool kids and nearly invisible geeks.

This milieu shaped the rise of what you might call aggressive atheism, the kind that mocks and dismisses religious belief. As Cimino and Smith point out, this outspokenness has helped atheism gain visibility and coherency as a movement. But it also has downsides.

"In accepting a label, particularly the label of 'atheist,' it seems to me that we are consenting to be viewed as a cranky sub-culture," said the writer Sam Harris at an Atheist Alliance conference in 2007. "We are consenting to be viewed as a marginal interest group that meets in hotel ballrooms. ... As a matter of strategy, we have walked into a trap."  

For the next generation of atheists, though, things might be different—fewer dinners of bad baked chicken at conferences, more Internet.

"Especially with young people … there’s an openness with respect to choosing your religion, as opposed to just staying with the religion you’re born into," said Smith. The Internet facilitates this: People who might otherwise feel isolated by the religious mores in their hometowns have access to communities of people who believe otherwise. "Atheists [aren't] loners without any sort of social networks," he said. "You can have social community, and social gatherings, without being in the same geographic meeting place."

This includes websites like Freethought Blogs and Reddit, which hosts a forum where people can post ideas and links about atheism. "According to its many testimonial posts, the forum known as r/atheism is a lifeboat in a sea of religious intolerance and incredulity," Cimino and Smith write. Topics include family and friends who aren't open to atheism, debates about social issues like abortion, and basic stuff like "atheist symbols other than the Darwin fish."

There are also downsides to these kinds of anonymous online communities. In a 2011 incident referred to as "redditgate," a 15-year-old girl posted an image of herself holding a book on atheism she got for Christmas; a number of commenters replied with sexually explicit remarks. Other instances of sexual harassment in the atheist community have raised questions about how friendly it is for women.

And in general, American atheists are much more likely to be male than female; in 2012, Pew estimated that about 64 percent of self-declared atheists are men. They're also whiter, wealthier, and more educated than the general public.

But they're also much, much younger. An estimated 42 percent of atheists are between 18 and 29 years old; in general, that age group only makes up 22 percent of the American population. Most other adult atheists are under 50; there just aren't that many self-professed non-believers among the Baby Boomers and beyond.

As thinkers like Sam Harris grow a following for less aggressive, combative strains of atheism, and as online communities of young non-believers grow, perhaps there will be less of a need for the shout-y, derisive brand of atheist activism. Whether or not that constitutes an awakening is open for debate; in the future, it might be closer to a "chilling out," a culture in which it's easier to be casually open about not believing in God.

Or maybe not. "For the near future, dialogue and empathy may have limited traction in a young social movement," the authors ultimately conclude. For members of a movement that's struggled to gain legitimacy and visibility in a deeply religious country, shouting may still seem more effective.