Virtual organizations (VOs) are groups of people who share a common computationally demanding or data-intensive goal. When you join a VO, you join a group of people who share a mutual goal.

To achieve their mutual goal, people within a VO choose to share their resources. This can give members of the VO direct access to the computers, programs, files, data, sensors and networks of other members. This sharing must be controlled, secure, flexible, and usually time-limited.

For example, a VO formed to develop a next-generation passenger jet will need to run simulations of various combinations of components from different manufacturers, while keeping the proprietary know-how associated with each component hidden from the other consortium members.

Another example is a crisis management team, called to respond to a chemical spill. This VO will need to analyze local weather and soil models to estimate the spread of the spill and determine its impact. They will need to create a short term mitigation plan and help emergency response personnel to plan and coordinate the evacuation.