Posted By:
HankronIn defense of eBay (for a change), they do offer the potential autograph bidder substantial information and resources. Before one bids, they offer a lengthy warning and advice ('Not all COAs are equal' etc) and also allow the bidder to get a second opinion from PSA/DNA or OnlineAuthentics before placing a bid ... So the potential bidder righfully bears much of the responsibility for his choices.
My most important advice for potential autograph buyers is always 'know your seller.' I find this even more important that where the LOA came from. And there are a number of top notch autograph sellers on eBay.