From a scientific point of view "a culture is the sum of all the factors that makes a group differ from all other groups."
In the case of virtual teams, we're dealing with cultural differences that are rooted in nationality, socio-economical, educational, organizational (corporate) systems, religion, beliefs concerning race, gender and lifestyle choices.
Even within our Western cultural sphere we encounter cultural clashes during corporate takeovers or mergers, ex. a clash between a more "democatic" and a more "autocratic" style of management.
There are many workshops and textbooks which help to get more acquianted with ex. cultures of other nations to facilitate mutual communication. However there are faster and better ways of developing operating methods using our workshops and consultations. Our consultants have worked at various corporations and with partners from many countries: in Europe (United Kingdom, France, Spain, Germany, Austria, Czech Republic, Sweden, Serbia, Slovenia), the United States, China, India, Israel and the Arab states.
If an organization is managed well, the cultural differences are not a disrupting factor, but they enrich the teams with new creative ideas inspire innovation.