I have heard of people using an "inverted method" with the AeroPress. Why do they use it?

People who use the inverted method do so to prevent premature drip-through of their coffee and to give them complete control over usually longer steep times. If you want to use a long steep time, we recommend using the normal method but insert the seal on the end of the plunger a half inch or so into the top of the chamber to stop drip-through while waiting for your longer steep time. The seal stops drip-through just like putting your finger on the top of a straw stops dripping out of the bottom of a straw. We think shorter steep times brew better tasting coffee but taste is certainly personal and people should brew their coffee the way it tastes best to them. Be advised that we recommend against using the inverted method because it is less stable and therefore prone to tipping over and exposing the user to hot liquid.