Coupling with the physical world is only one of the challenges for information technology - each MEMS application poses its own unique set of information technology requirements. We looked at a variety of applications and found that these five factors were the ones that most influenced the demands placed on information technology. For example, in the case of airborne surveillance particles, part of the challenge is a time-varying spatial configuration (e.g. dynamic topology). For active aerodynamic surfaces, control is complicated by the dynamics of the fluid being manipulated, and by the need for actuators to take on different roles depending on the location of vortices (e.g. varying logical organization and coupling with the physical world).