"... First, there is the scenario where we have a small atheist-owned business and must contend with the owner potentially losing customers when his or her atheism becomes known. And second, there is the case of an atheist being employed in a company where most of the prejudice encountered would be expected to come from co-workers and bosses ...
The Atheist Employee
I'll speculate that most atheists employed in the U.S. either have faced some sort of prejudice in their place of employment or remain closeted at work in order to avoid this outcome. I've encountered prejudice of all kinds at the state university where I am employed (e.g., race, age, sexual orientation, gender, and atheism). What stands out to me is that most people seem to know that it is inappropriate and try to conceal it, except when it comes to atheists. In fact, I've heard more than my share of anti-atheist bigotry right out in the open (e.g., atheists are immoral, can't be trusted, evil people, etc.). People do not seem to put it in the same category as other forms of prejudice and have few compunctions about expressing it openly.
I have also heard from friends and family of far more serious examples of prejudice and discrimination against atheists in the workplace. These include repeated, unwanted invitations to attend church with the boss, mandatory attendance at sectarian prayer meetings during work, open hostility from co-workers including threats of hell, and even termination.
Particularly here in the South, being an open atheist can be an excruciatingly difficult experience in many places of employment. At the same time, being an openly evangelical fundamentalist Christian is often encouraged, sometimes explicitly so.
... I'd guess that it would be virtually impossible to run a small business in a small and rabidly Christian community as an open atheist. I've heard many stories of professionals in such settings losing clients after answering questions honestly about their views on religion.
I would expect the experience of atheist business owners to be highly variable by region. In a large city in a more educated part of the country, I suspect one could do okay even while being reasonable open about one's atheism. Customer word-of-mouth and the involvement of churches might be less important in such settings ..."
Being an atheist, a business owner, and a former employee, I can speak to whether these situations are applicable to my case. The definition of an "open" atheist is difficult as I don't actively advertise that I'm an atheist, but I also don't actively hide it. Part of that is the difference in how one's faith (or lack of) informs their daily life.
With Christians, and I don't think I'm speaking out of turn here, your religion does influence most things you do on a daily basis. It certainly affects how your children are taught, how you handle work situations, and what movies you watch and what music you listen to.
I can honestly say that I go through life and religion doesn't factor into my decisions at all, except when someone else's exercising of their religion intrudes on mine.
I have not personally been descriminated against overtly for my atheism and that is due to several things: 1. My employers and clients don't know I'm an atheist because I don't go around with an atheist patch 2. The computer/software industry is fairly open-minded. When I say "overtly", I mean that no one has personally ridiculed me for being atheist. But, if you define descrimination to include unwanted invitations and professions of faith, I get that on a daily basis.
As a Christian, would you be offended if a Muslim or Jew invited you to their church or expressed a religious belief without being asked? I suspect that many would. I guess most of that doesn't bother me because I don't elevate it to the importance that people of faith would. Someone talking about their preference of religion is no more important to me than if they said they were a Yankee fan. In both cases I may think they were nuts, but c'est la vie. To each his own.
I'm not sure what point I'm trying to make. I guess the gist of it is, I personally think business is not a place for expressing your religious tastes, for or against. You are free to believe what you want, but when it impedes on others doing the same, then you have went too far.
"We must respect the other fellow's religion, but only in the sense and to the extent that we respect his theory that his wife is beautiful and his children smart." -- H. L. Mencken