Pod-Style Coffee Makers
This type is the simplest to use: You just drop in "pods" that are pre-filled with coffee grounds. Keurig makes the most popular line of pod coffee makers and their K-Cups can be used in some other pod-style coffee makers as well (and there are a number of generic pods that will work in Keurig machines). The pods are inserted into a holder that, when closed, pierces the pod with needles. Hot water then flows through the pod, brewing the coffee into a cup placed under the spout. Some pod coffee makers have a reservoir so you can brew multiple cups before refilling; others need water added before each cup is brewed. Pods come in hundreds of varieties, including cocoas, teas and fruity drinks -- some are intended to be served iced. Pod coffee makers can also dispense plain hot water for making tea, instant soups or hot cereals.Multi-use Single-Serve Coffee Makers
Some pod-style coffee makers are more versatile than pod-only machines and can both brew ground coffee and accept K-Cups. There are even a few drip-style, single-cup coffee makers around; the most popular of these are smaller machines that brew directly into a thermal travel mug for to-go convenience. These types of one-cup coffee makers are not as common as pod-style, single-serve coffee makers, but people who want the convenience of a one-cup coffee maker, yet don't want to be tied only to pods, like these machines. They tend to cost less, overall than pod-style coffee makers, but they don't get as good of reviews in general for performance, with more complaints of leakage and messes than with pod coffee makers.