What causes excess earwax buildup?

The skin cells lining our outer ear canals include tiny glands, similar to sweat glands, which produce wax. The point seems to be that this acts as a protective layer, just like mucus protects the nasal passages. This layer traps dust and other particles which get into the ear. The wax slowly works its way to the outside, taking the trapped dirt and dust with it. Most people's ears clear the wax, which probably comes off on our pillows and towels etc., at a rate which means that it does not build up. Some people may, at some stages in their lives produce wax at a faster rate. Other people have either one or both ear canals that is narrow, or that is at an angle which slows the natural passage of the wax. In these people the wax builds up. The wax may eventually block off the ear canal all together. If this happens, hearing is reduced, and there is an increased likelihood that stagnation may lead to an infection building up behind the obstruction. Just wanted to add that the inside of the ears have hair follicles and they trap the dirt (and the process goes on exactly as the above poster described it). Many people don't realize that when they listen to extremely loud music or are in a loud theater they can damage these hairs and this can cause deafness at an early age.