A tiered stand is pretty much like a pedestal cake stand but with more than one base where you can place cakes in, and is usually the best choice when cupcakes are involved. The bases gradually grow smaller as the stand grows taller, creating the illusion of a dessert tree or pyramid. Cupcakes are placed on the bigger bases, and a small actual cake is placed at the top_most base, or sometimes the entire stand is filled with just cupcakes. In place of cupcakes, petit_fours or other small pastries can also be displayed in this type of stand.
These different cake stands can actually be used for any type of event when decorated accordingly, but you need to take three things into consideration: 1) the kind of event you're planning, 2) the kind of cake you're having for the event, and; 3) the 'look' you wish to achieve with your display. Once you figure these out, you will then get a clearer picture of what cake stand you need, and what you can do with it to achieve the look you are aiming for.