The European Court of Justice has ruled that consumers have the right to resell downloaded software as "used", even if the software is sold under a license that prevents it.
The case  (pdf) concerned Oracle, the enterprise computing company, which sued a German firm UsedSoft. Oracle allows customers who have paid for a license to download copies from their website for use on up to 25 computers, as well as offering free access to updates, and it does so under an agreement which gives the customer "a non-transferable user right for an unlimited period, exclusively for their internal business purposes".
UsedSoft allows that license to be resold, contravening Oracle's agreement. It buys the access to the download site from users, and sells that access on.
The court was asked to consider whether the European first sale doctrine applies to downloads. For physical goods, it has long been held that exclusive rights to distribution are exhausted after the first sale. So, for example, HMV can have the exclusive right to sell One Direction's new album, but they cannot prevent you buying the album and then selling it on yourself – even if they make you sign something beforehand. It decided that when a right to use software for an unlimited period of time is exchanged for money, that constitutes a sale, and thus the first sale doctrine applies.
Importantly, the court also ruled that the right to updates is sold on, preventing one possible route around the judgement. Oracle must treat owners of second-hand software the same as those who buy it new for the purpose of software updates.
The right to resell still requires the first owner to remove the software, and it doesn't allow you to "split" multi-user licenses and sell off unused capacity. But it is nonetheless a major blow for users in the digital age.
However, although the judgment gives users the legal right to resell software, it doesn't mandate that retailers make that right practical to exercise. If you want to resell your copy of Angry Birds, you'll have to give your entire iTunes account over to whoever wants to use it. A thriving resale market is unlikely to emerge anytime soon.