“Cloud bursting” is a new term that describes leveraging compute resources external to an organization, when the demand is greater than the organization has capacity for. Basically it is a process that provides additional resources that an organization doesn’t typically pay full price for the additional resources initially, but pay based on a consumption model when those additional resources are used.
Is IT the only organizational unit that does this?
Nope, not by far. Scaling quickly during a time of increased demand isn’t really isolated to just infrastructure and technology units. It has been around for a long time. In fact this practice has been around a long time, longer than most IT departments have been around.