Abandonware is the distribution of computer games and other software that is no longer sold or supported, or whose ownership may be unclear for various reasons (company closed or merged). In the beginning of the World Wide Web, there was a debate that considered Abandonware the same as piracy. In my opinion, Abandonware is a good thing and I believe it is possible to come out firmly in favor of Abandonware but totally against Piracy.
First of all, Abandonware is illegal. According to copyright legislation, a copy of any creative work requires the consent of the creator or owner. Abandonware goes against these laws by distributing computer games that for the most part no consent was given. Participating in abandonware is to break copyright laws.
The problem is that people confuse software Piracy with Abandonware. Piracy is automatically illegal because the distribution of the software is done without the consent of the creator or owner.
Just because both are illegal does not mean they are the same thing. It all comes down to intention of the lawbreaker and who is the the target or victim of the crime.
What are the intentions of an Abandoneer (my definition of a person who participates in promoting Abandonware) and a Pirate? An Abandoneer is targeting software that is no longer sold or supported by the creator/owner. In contrast, a Pirate is targeting software that is currently being sold and promoted.
Who is the victim and what is the harm done? For every pirated copy of software there is a reasonable assumption that a sale has been lost. Those sale losses harms the profitability of the company that created the software. Instead of reaping the market rewards they have the potential to get, their viability is harmed.
For a law to be just it must protect victims. Breaking a law that does not harm anybody may be illegal but it does not mean it is wrong. There is a world of difference between what is legal and what is right or just. Laws have been written to justify doing the wrong thing, like the old U.S. Jim Crow laws.
Distributing computer games that was written in 1985 harms nobody. Because the software is no longer being sold and thus is not generating any revenue there is no harm and thus no victim. The purpose of Abandonware is to preserve creative works for posterity or to share a gaming experience that has not been duplicated. Abandonware is not the same as Piracy. While there is no doubt it is illegal, this is a case where being the outlaw is not the wrong thing to do.