This is more globalization as opposed to diversity, but you are kind of getting the point. Diversity is about using all Human Resources to their fullest potential. But what most corporations usually want is the best work for the cheapest price (don’t we all). And to get there, they go delving into “diversity.” They also do the visa thing.
It is also about wanting to know the best way to reach out to a diverse customer base. Money is money. Lots of people have it. But in order to get it, the corporation has to understand those different types of people, different cultures, different communication styles etc.
Corporations have long ago figured out that women work, harder for less, and therefore women (white women actually) have been the biggest beneficiaries of affirmative action.
Because corporations are always wanting more for less, they dig diversity. As the workforce has becomes more global, they definitely are interested in getting the best workers from wherever, and that often means not American white males, and often times not Americans at all.
The truth is we are living through drastic economic shifts, and the American workforce is under a tremendous amount of pressure to adjust. The more comfortable you are with diversity and multiculturalism, the more of an asset you will be to any corporation, because the corporations are multinational and multicultural, at the higher levels you have to understand that kind of diversity.