So recently, the Court of European Justice had to rule in a legal catfight between Oracle and a german shop that specialized in reselling "used" Oracle licenses. Oracle, being the kind of dicks that you would expect them to be, was convinced that since they were technically not selling anything, just granting people unrestricted licenses to use their software, reselling those licenses was bad. And wrong. Possibly badwrong.
Enter the aforementioned court.
In a ruling that is far too legalese to be understood by people without a lobotomy, the court ruled that the process of granting such a license is in no way distinct from actually selling those products, thus making it clear that the company selling that license has no control over what happens to it afterwards.
What, you may ask, does this have to do with you? Simple. It means that, just like you can resell games you bought as physical copies,
you have to be able to resell games bought on a purely digital service, like Steam or Origin.
In short, what you buy in those stores is your property, and you are free to do with it as you wish. Yes, this ALSO means that the distribution services have no right to remove your access to those games (As EA is prone to do).
Now, it'll take some time for this to filter down into consumerland, but the basic ruling is there, and can be referenced in future cases.
Which is awesome.
For a more in-depth discussion, refer to
this article on Rock Paper Shotgun.
EDIT: Oh, I should also note that this has no bearing on subscription-based games or game services (Games like WoW, Services like OnLive).