My experience with Ebay must be different than yours. I have had no trouble at all with Ebay, but I read descriptions carefully and pay attention to the seller's feedback. Selling, just be double-darn sure that the payment is clear before releasing the merchandise.

In my experience, Craigslist is Scammer Central. I still sell and buy there, but you need to have your eyes open extra-wide. Cash face-to-face is the best way to do business there.

In a related vein, when you get the scam emails("Do you still have your item for sale?") from a CL ad, what are the scammers hoping to gain? Is it just to get a valid email when you reply?  Are email addresses worth that much?