David's post about Christianity, Judaism, and proselytization gives me an opportunity say a few words about the interesting subject of whether atheists should proselytize for their position. The strong pro-proselytization stance of atheist writers such as Christopher Hitchens and Richard Dawkins leads many people to assume that proselytization is an inherent requirement of atheism, or at least that most atheists put a high priority on persuading theists of the nonexistence of God. Neither claim is true. The majority of atheists have little or no commitment to proselytization. And to balance Hitchens or Dawkins, there are atheist philosophers such as Michael Martin, who defend "friendly atheism" - a generally nonconfrontational approach to theists (for those who may not know; Martin is one of the most important contemporary philosophers of atheism).
Believing that God doesn't exist does not commit the atheist to also believing that it is important to convince others of this truth. There are many false beliefs out there; we can't make a priority of changing all of them. Many are better left alone because they cause no harm or because our time and effort is best devoted to other matters.
One possible justification for atheist proselytization is that religious beliefs are often used to justify harmful practices. For example, various religions have defended slavery, sexism, racism, and religious intolerance. This is true enough. But the same can be said for various secular ideologies that have also promoted injustice. One of the weaknesses in Dawkins' and Hitchens' claims that theism is a uniquely dangerous source of harmful beliefs is their failure to come to grips with the record of harmful nonreligious ideologies such as communism and fascism (note that "nonreligious" does not equal "atheistic" - most fascists, for example, were theists; it merely means that religion is not an essential part of the ideology).
Atheists can and should oppose harmful religious beliefs. But they should also oppose harmful nonreligious ideologies. Belief in God does not in and of itself commit the theist to supporting injustice, anymore than rejection of that belief commits an atheist to any particular ideology or moral system. Atheists (and theists) should make it a priority to reduce the influence of dangerous religious ideologies such as radical Islamism. That is not the same thing as putting a high priority on reducing belief in God in and of itself. If adherents of radical Islamism abandon their views in favor of atheism - as Ayaan Hirsi Ali courageously did - well and good. But the same practical results could be achieved if they instead embrace a more liberal and tolerant version of Islam.
The key point is that one does not have to be an atheist to be a moral person or to oppose injustice. Atheism is neither a necessary nor a sufficient prerequisite for either.
An alternative justification for atheist proselytization is that religious belief can impose unnecessary costs even when it doesn't lead to any coercion or injustice. For example, some theists obey strict dress codes and dietary laws out of what atheists must regard as a mistaken belief that they have been ordered to do so by God. Persuading these people of the validity of atheism would free them of unnecessary burdens. In some cases, it could even radically transform their lives for the better. Consider the case of Hirsi Ali and other women who come to reject religious doctrines that justify drastic (even if voluntary) restrictions on the role of women in society. Here too, however, the problem is not belief in God in itself, but the theist's secondary beliefs about what kind of behavior God commands. The latter, not the former, should be the primary target of reformers. Moreover, most voluntarily accepted religious burdens don't exactly rank high on the scale of serious social problems. We have vastly more important fish to fry than the possibility that Jews who keep Kosher are needlessly foregoing the chance to dine on lobster.
Finally, it is worth mentioning that aggressive proselytization could damage our image and our relationship with theistic groups, many of which have a lot more political power than we do. This would be a risk worth taking if proselytization were a vital moral imperative. But since it isn't, the pragmatic dangers of overly aggressive proselytization should not be ignored. I don't myself believe that aggressive proselytization (of either the atheist or the theist variety) is morally reprehensible. But I'm in the minority on that point. There is no reason to needlessly antagonize those who think otherwise.
My bottom line: Atheists should not hesitate to defend the validity of their beliefs when challenged. And we should actively combat anti-atheist prejudice and discrimination. But I don't see any compelling reason to make a priority of atheist proselytization.