Location, Location, Location
An over the range microwave is a microwave oven that is mounted over your stove top. This places it in a very convenient location, saving your counter space for other appliances.
If a home is built with an over the range microwave, the appliance is usually wired directly into the wall, eliminating hanging cords. If not it is easy to drop the cord through the wall to an outlet. Over the range microwaves are set up to keep all the clutter out of your way, with a plate and mount system that routes wiring to the wall.
Having an over the range microwave provides a range light as well as exhaust fan for the stove area. This means not only is the microwave a convenient cooking appliance but that it also does duty as a range hood. Given the location of the microwave it tends to be a bit larger than standard countertop microwaves, which will allow you to cook larger items.