Once again, an apology if my search somehow missed these answers, but it might be nice to have them in one place anyway.

I am only buying games on GOG at the moment, in no small part due to their lack of DRM. I hear of other services being bandied about in posts, so I am curious as to which of these have DRM, and of those, how is it implemented? (Does it require you to install an extra client that the games won't run without, does it need to you to online and play through a server, things like that.)

The vendors I've heard mentioned are:

Desura
Steam
Gamersgate
Humble Bundles

Please add any other vendors and their info as well, if you like.

Thanks!

Desura - most games have separate DRM-free installers that you can download from the game's store page if you own it

Steam - all games need the client to be downloaded. Some have Steamworks, which is the DRM that requires Steam to be open to play them. Others can be run without opening Steam. Here is a thread with those games that are DRM-free on Steam.

Gamersgate - they sell DRM-free games that you download the installers like on GOG, but they also sell keys for services like Steam or Origin which do have DRM

Humble Bundles - nearly all games have DRM-free installers as well as Steam keys. Few are only Steam keys, and some aren't on Steam (yet).

Gamersgate - Has no DRM of it's own, but some games come with DRM from the publisher. Second best option after GOG, has tons of games that either have no DRM or just some minor versions (1-time serial key activation)

Desura - Most games, probably more than 98%, are DRM-free

Indiegamestand - Almost all the games ever sold here have a DRM-free direct download

Humble Bundles - All games come with DRM-free download links, along with Steam/Desura/Whatever keys

Dotemu - Kinda like GOG, but smaller

Gamersgate has a lot of good, less known games that are dirt-cheap even at base price, like Harbinger, Genesis Rising and others. Definitely the best site after GOG.

FireFlower Games sells DRM-free games for Windows, Linux and Mac for direct download.

Humble Store is the best DD store out there. They give you a choice in how you want the game (DRM free where possible, and keys where available) and they are the store which gives back most to the developers. Latest news/rumors says that selling through HS gives the devs 90%, while Steam and GoG gives ~75%.

The problem is that HS have no front-end, so it is a bit of search to know which games are there. the games are sold through a widget on the dev's site, but you get an account in HS where all your purchases are collected.

Edit - Shiny Loot is also DRM free - http://www.shinyloot.com/

Well, you can go here.
I know, not the best solution, but...

Didn't know about this one, thanks.


EDIT: typo

Both of these are new to me and look quite promising. I'm frankly amazed that in these days of supposed rampant piracy that there are all these DRM-free game sites. It's a very heartening sight indeed. Much thanks to both of you!

Of the four you listed, only the Humble Store (and Humble Bundles by extension) sell DRM-free games as a rule. And in the case they sell games that do have DRM (as with the THQ bundle from a while back), it's made very clear to you before you buy.

Others here have said that Desura and Gamersgate also sell DRM-free games, however that is not really true in either case. Desura has no policy for or against DRM (some games have it, some don't) but what's bad is that for the games that do have DRM, it's almost never explained anywhere on the store page. So you could end up buying a game that has DRM and not know it until after it's too late.

GamerGate, meanwhile, has DRM for all of their games, since you have to connect and log into the GamersGate servers to both download and install the games. There may not be any additional 3rd-party DRM on top of it, but the basic GamersGate DRM is always there, which is basically equivalent to Steam (if GamersGate ever goes down permanently, you will be unable to install any of your games).

I believe it's been mentioned on another part of the forums, unfortunately not sure where now, that the GamersGate DRM is not quite as strict as all that, compared to Steam. Sorry if I'm wrong, but I'm sure I read it somewhere on here.

This should be expanded on a little bit. Gamersgate doesn't provide you with simple executable installers like GOG does, but instead basically gives you a file that acts like a download manager and downloads the actually installation files to a temporary folder. The executable for the installer is downloaded in an encrypted form, and is only unencrypted at the very end of this process, then once the installation is complete the unencrypted version is deleted. Even if you save on the remaining files you still need to basically phone in to the Gamersgate servers to install the game. Now, this is pretty easily circumvented, by copying the installation files to a new location once the installer has been decrypted but before the installation process is complete, but it's something that you need to be aware of.

And this is just regarding the Gamersgate installation process; many games on Gamersgate have some kind of additional DRM beyond this, although it's typically mentioned on the info page for the game.

I joined Gamersgate simply to buy the old X Com games - sadly not available (yet) on GOG (otherwise I'd have bought them from GOG but I couldn't wait forever) and they are supposed to be DRM-free. They are not totally DRM-free without a bit of hassle, however, and I do not yet myself have truly DRM-free versions of these games. You buy them from GG and then attempt to download them. Instead of downloading the actual games straight to your computer, however, you are in the first instance made to download LINKS to the actual games, from which links you can then download the games to your computer. You can then download the games from these links, but if you ever want to uninstall the games and want to install them later you will have to do so via the links, which links force you to connect to Gamersagate again every time. So in this case at least GG "DRM- free" is NOT DRM-free : at least not until you know a few tricks (but why should you have to ?) There is way round this and I learnt it through the GOG forums (and I'm grateful for the help), though I haven't tried it yet, so I can't confirm that it works. So you can buy DRM-free games from Gamersgate and they can turn out to be (truly) DRM-free - but only if you know how to make it so. And it is not obvious to the ordinary user.