Re:
Mike
You've asked yourself what is shill bidding? And how does it effect you.
In simple terms shill bidding is basically a seller, who uses another user I D: they have set up (and may have multiple accounts) which they then use to bid on their own listings or gets someone they know to bid on their listings (when unsuspecting bidders have placed a bid) in an attempt to increase the final price of their item. In some cases the seller ends up winning their own item because of their greed.
How often have you used an auction site to find an expensive item listed cheaply, which you have bid on and won at a bargain price?
How often have you seen expensive items listed for .99p, which inevitably sell for their guide and book price or higher?
Would you list a valuable item for .99p without a reserve?
You also need to be aware items with a reserve can easily be shilled.