Article from Texas Instruments on various common misconceptions about Hall-effect sensors as well as real-world applications. Link here (PDF)
Hall-effect sensors are commonly used in automotive and industrial systems for applications including proximity detection, linear displacement measurement and rotary encoding. Currently, the high system performance requirements of modern applications have led to IC manufacturers increasing sensitivity accuracy, integrating more functionality, expanding available sensing directionalities and lowering power consumption in their devices helping extend the use of Hall-effect sensors for decades to come.