What I find intriguing about all of this - is that the selling of pirated software on ebay is playing into the hands of the politicans who want to start increasing control over sites like ebay. There is a politcal push to require proof of original purchase before posting an item on ebay. Also, some states have actively looked into how to charge SALES TAX on any auctioned item - even thought the sales tax was paid when it was originally purchased. All of these examples of illegal software sales will just add fuel to the fire.
Unfortunately, for 90% of the stuff I sold on ebay over the years - I did not have the original receipt. I have a Commodore 64 my parents bought me for Christmas and never even saw the receipt.
Also, software is going to digital licensing to your account. Soon we will only be able to get it via Steam for PC or PSN/Xbox Live distro. The days of buying software at the store is going away. The days of buying used console games will come to an end within 5-10 years too.
Oh well, just get ready to have to spend a lot more than ever before to obtain media (games, music, books) etc in the future.