«

[Japo]

Just to clarify, in principle it's legal if the licence agreement allows it. The licence agreement is the contract you implicitly sign when you click on "Yes/I agree" while installing the software. A licence agreement could include a clause of non-transferability, prohibiting you from re-selling the licence. Most actually include a clause of transferability, allowing you to re-sell the licence with conditions--to a single person--and of course if you sell your licence you'll no longer have licence to use the software.

Software is different from other goods, usually it's never sold itself, the only thing you can buy is a licence (permission granted by the owner) to use the software; but the software itself remains the property of the party that grants you the licence. This is because if they sold the software itself entirely, they would have no legal device to prevent you from doing anything you fancy, for example copying it.

Even "open" licences reserve the ownership of the software for the author, to impose conditions on the distribution. In open licences distribution is "free" to multiple persons, only if you adhere to those conditions.