Communications satellites orbit directly over the poles, how does this help it to do it's job? And for a weather satellite directly orbiting over the equator?
Not all communications satellites orbit over the poles. Some are in geostationary orbits like the GOES weather satellites. Satellites that need to "see" all parts of Earth (but not all at once) travel in relatively low-altitude, near-polar orbits, with Earth turning beneath them. That way, during one complete Earth rotation, nearly every part of Earth passes beneath them. Want to learn more about orbits? http://scijinks.gov/orbits