This is all a shame for the law-abiding retro game fan, because emulation is a pretty great way to enjoy the games of your youth. Some players try to limit their ROM downloads to fair use 'backups' of cartridges they already legally own, but even this is a bit legally questionable if you're downloading someone else's (largely identical) copy of the game rather than copying the physical cartridge you actually own (though it's hard to find much actual case law dealing with this wrinkle of digital game archiving). While the emulators themselves are generally accepted as perfectly legal, downloading copyrighted ROMs generally isn't OK, no matter what your cousin told you about a '24-hour trial period' exemption or abandoned copyrights.
If you're a retro game fan who cares about obeying the letter of the law, emulation is a veritable minefield.
