I see a lot of people selling Bitcoin on eBay. Since the government began regulating exchanges, are there any rules you have to follow now to sell Bitcoins on a site like eBay? Additionally, are there any rules you have to follow when buying from eBay?
According to eBay's Stamps, Currency and Coins Policy:
Virtual currency must be listed in the Classified Ad format in the Coins & Paper Money > Virtual Currency category. These requirements apply regardless of whether the virtual currency is digitally or physically delivered. Examples of items subject to this policy include Bitcoins, Litecoins and other similar cryptocurrencies.
In particular, it appears you are currently not allowed to auction Bitcoins.