You almost certainly know some atheists. (And not just on Facebook.) In the U.S., non-believers are about 10% of the population. You almost certainly have atheist neighbors, co-workers, family members. If you think you don’t, it’s because atheism is stigmatized, and many atheists don’t feel comfortable or safe revealing their atheism. Pass it on: if we say it enough times to enough people, it may get across.