Which is still arguably a form of rights management. I think more that DRM today is an umbrella term, which does include copy protection. It did not have that term back then, as it did not need it, but there is so many different schemes today that such an umbrella term is needed. Under this umbrella term you can then make several distinctions - such as physical copy protection, account based, always online, disk based etc.

Not necessarily only the person who owns it, no, but you're right that this measure ensures that the game can only be played by one person at a time, provided the disc also has copy protection.

I think the terms have always been a bit vague, even back in the 90's with all the code wheels and such when you'd talk about "copy protection" (at least in Germany we did), although strictly speaking these measures didn't prevent you from copying, just from playing a game without having access to the manual and other stuff from the original package.

This is an important topic because not all DRM is disruptive. CD keys are definitely DRM, they are a method which publishers have used for many years to enforce the end user agreement between the company and the customer. It is not fool proof, but it is reasonable to expect mostly paying customers to have unique CD keys. CD keys are not actually disruptive because they do not add unwanted or unannounced 3rd party software, and they are usually LOCAL solutions, not depending on internet communication and no oversight from a 3rd party (like the game publishers or store).

Most people think of "the game" or the disc to be the product. It is not. You are buying a license to use the software under certain conditions. The good old CD key exists in a vacuum, the software only caring that you type in one of the hundreds of thousands that exist. Other methods of enforcing the license however are not self-contained. This is where you have your software stop functioning unless it can repeatedly communicate with the publisher to make sure it is being used as agreed upon. This gets downright bizarre when the license stipulates that you may only install the game on one computer and the DRM solution is CONSTANTLY harassing you to see that you are not breaking the rules.

While DRM can be a headache, the big danger is that when the DRM malfunctions, or in case of DRM that relies on internet authentication, if the third party disappears and your game can no longer be validated for reasons that are out of your control you have a non-functional game.

GOG has a few games that use CD-keys to allow online multiplayer. GOG has no games with DRM that is under the risk of malfunctioning for reasons out of your control, and no games that install additional intrusive software that spies on your game ready to put a foot down when you appear to be in breach of contract. You buy a license to use the product, GOG provides a download link to the install files. They trust us to be mature and honest in our handling of the software licenses, no need for oversight.

People checking in today and I have to go do some actual work, BUT BEFORE I DO, the obligatory funny DRM pic. :D

Only applies to single-player games.

DRM is a online technology introduced in 2004.
Before 2004 you had no DRM but rather copy-protection, either disk based or some manual/card check.

DRM for me is:
a single-player game requiring internet to install or/and play at least once.

DRM-Free for me is:
standalone offline installer and game with no measures to prevent copying for personal use.

Are serial numbers DRM?
Some call a serial number DRM, or DRM-lite and I disagree.
A simple serial number falls in my definition of DRM-Free.
Serial number and product activation are two completely different things.
Product activation checks a server for authentication using the internet.
Serial number or CD key is only checked locally by the offline installer.

I might be living under a rock, but what does this refer to?

????

I agree with this side of the argument. I don't agree the digital in DRM = Internet, digital is for the digital product. Previously they managed your product by restricting it to the disc it came with since that was about the only thing they could do. Now they're doing it through accounts and online authentication. Both are DRM imo, just different forms.

When people on GOG speak about DRM they 'mostly' mean the online form though.

I hope you put on your most charming face for them. ;)

Well, wikipedia says So, In case of a game, I think that everything that does not allow you freely copy or play game - is DRM.

So what about optional features that rely on an internet connection (achievements, social features, character backup, etc). Are they a form of DRM?

Not in itself, no. (DRM is never optional, btw.) But if they're not optional and the game relies on them, they can have the same consequences as DRM (e.g. loss or lack of internet connection interfering with your ability to play the game, and abandoned support effectively killing it).

If you still able to play and copy this game - then it's DRM-free.

Nope, not at all. Look at the phrase you included: "optional". And none of those require DRM. A lot of those things were in 3rd party clients/systems (see: XFire) before they were INTEGRATED into the Steam DRM system, where now people, sadly, think DRM is required for them.

The Sims 3 is a DRM-free game (disk versions anyway; not the downloadable versions), and it has optional social features and achievements you can enable and disable as you choose to.