Another advantage to selling through an online auction is that the auction operator often provides services for you that would be much more costly if you procured them yourself. For example, some of the major auction sites allow you to accept credit card payments without requiring you to establish a merchant account with a credit card processor. With a small, unproven business, setting up your own merchant account can cost a pretty penny. Of course, the auction operator gets a little extra piece of the action, but that's to be expected. And that doesn't even factor in how much easier it is to accept payments in this manner.
Businesses also have distinct credibility advantage compared to individual sellers.
Online auction fraud is still a big problem - big enough to scare some people away. In most auction frauds, it's the seller who's doing the defrauding. Before you start selling online, I strongly suggest you take some time to do your homework first. Make sure, for example, that you understand the terminology. Understand the terms and you'll better understand the process.