The top EU court says you have a right to resell your downloaded software. According to Ars Technica:
The European Court of Justice has that customers have a right to resell software they purchase regardless of whether the software was originally distributed on a physical medium or downloaded over the Internet. The ruling is a defeat for Oracle, which had argued that the court should uphold provisions in its license agreement prohibiting such transfers.
That's just silly. The software industry is right when it says software is licensed not sold. Software is in digital form so it never degrades. When you sell a car, or even a book, the physical degradation of the item takes care of valuation on the used market. But software is different. Once you buy it and use it, you have received what you paid for. Sellers of software licenses should be able to forbid their resale.