Ebay Auctions
For a long time this was the only way to sell things online. It still has the most traffic and generates by far the most sales. However, over time, growth has limited flexibility, and corporate vision has changed. More and more sellers are finding it difficult to sell profitably there. The fees increase, there are more and more restrictions and rules, charge backs are an issue, etc.
They still have the largest number of buyers so I don't think avoiding them entirely is an option. To me, that suggests I should look for the best tools available to work efficiently within their system.
There are also a lot of nifty Ebay plugins for Wordpress sites. Below is an example of a link to specific auctions going on now on Ebay.