I see a "Windows 7 Compatibility - Work in Progress". How about a Linux/Wine compatibility? I'm just buying games here that are running on Linux/Wine which are quite a few.
Like CaesarIII, Tropico, Fallout1+2, etc.

You just need to go to http://www.winehq.org/ and look for Gold/Platinum games and add that to the description of your games. Maybe a small penguin logo with platinum or gold games?

We have several different Linux lists going, but in the interests of condesing them, the best on is probably this GOGmix by paldepind:
http://www.gog.com/en/mix/great_gog_games_that_works_on_linux

As for GOG adding any kind of offical Linux seal to the games, that will never happen... at least it won't happen anytime soon. In order to do that, GOG would have to both test and support the games on Linux, which they currently do not and probably can't due to their limited resources.

The funny thing is that for some games they include all that's required to run the game on Linux. Namely, source code for DOSBox :)

I've said it before and I'll say it again: gog should add Linux and Mac support for games that use DOSBox (and ONLY those games - if you'd need windows emulation to run the game on Linux/Mac you might just as well run the windows installer the same way) anyway to run on Windows. There is just one serious problem that I can see: the installer.
I see 3 possible solutions:

1) 3 versions of the installer (1 for each system)
pros:
- little to no development time, if using existing solutions (BitRock for example)
- no changes required to existing gog releases
cons:
- some additional work required for each new DOSBox-based release

2) split the installer into 2 files: a universal installer (1 for each system) and data files
pros:
- easily extensible system
- possibility of bundling DOSBox with the installer - updating to newer DOSBox version for all games requires changes just in the installer
cons:
- development of installers

3) add an advanced "installer" for Linux and Mac that rips out the game data from an existing windows installer and attaches a system-specific DOSBox version
pros:
- no changes to existing packages
- no additional work later on
cons:
- a LOT of work (possible reverse-engineering of existing installers, creation of icons and links based on what windows installer does, etc.)

We are still going to come back to the problem of testing and supporting the games on those systems, which for an operation that only has 20 employees and has a tough enough time keeping up with their Windows-only library, is very likely going to be much more work than they are willing or able to accomplish. Additionally, you are making the huge assumption that there are no legal hurdles that prevent them from releasing these games in an alternate OS format. For all we know, their rights to sell the games only applies to selling them in a Windows installer format, which may be why they have always balked at releasing the games as a simple zip file that could be used on any system.

If they limit themselves to games using DOSBox then they only need to test and support one piece of software - DOSBox. Modifications required to the configuration files of the windows releases could be done in 10 to 15 lines of bash script at runtime (It took me 10 minutes to check what would need to be changed and write some proof-of-concept scripts so It's not rocket science) Okay I chose to ignore the possible legal issues and only approached the problem seeking technical difficulties.

If there are legal issues in distribution I wonder if it would be possible for gog to include some sort of indicator how hard it is to make the game run on Linux/Windows. It should be community-based (average of x last user ratings displayed - little additional work from gog and accounts for ever-improving windows "emulation"). Although I have to say that GOGmixes are a step in good direction (assuming the creators can change them - I haven't tried making a GOGmix yet so I don't know).

Yes, creators can change them. The one that paldepind created is still being updated with new entries every time someone finds another game that works. Again, you are making another assumption, that the GOG guys even have Linux machines to work with. As a Windows-only shop, it stands to reason that they do all their development and testing on Windows. While it may seem simple to you or me, the reality is, it might be much more complex than either of us think, especially if GOG does not already have a "Linux guy". Plus, GOG has an "all or none" approach to most things here, meaning if they are going to support other OSes, its likely going to be for all the games in the library or none of them. Splitting the library is not the kind of thing they like to do.

I'm not saying Linux or Mac support can't be done, just that it is unlikely to happen and unrealistic to expect it from a small company like GOG.

It's not a bad idea. But I seriously don't think it's worth the work.

I've been playing lots of GOG DOS titles on Linux and I've never felt a need for DOS titles being officially supported on Linux. Finding out what games works are DOS games isn't harder than just looking them up on Wikipedia. And they're quite easy to install too. You'll just have to run the installer with Wine and then copy the game files to you DOSbox folder.

So official Linux support would only save me about a minute for every game I install. On the other hand I'm sure it would require quite a lot of work from the GOG team and as cogadh pointed out they don't have that kind of recourses.

I'm just asking, if enough people asking maybe they add support. I'm just a consumer.

At least GOG.com don't use Flash/Silverlight or some other crap to download and install the games. Just plain ZIP file would do the trick, too. Don't know if there are stupid rules about showing the EULA or some other legal stuff to follow. Thank you for the link, I didn't know GOG.com have such lists. But there are a few missing.

* Caesar III
* Tropico 1&2
* Perimeter
* Divine Divinity
* Sanitarium (DOSbox)
* Spell Force Platinum

Thanks a lot! I've added them to the list. Did you test these games yourself? And if yes, I'd be happy if you could give me more info. For instance, how well did they run? On witch distro and what version of Wine did you use? Any tips that could be useful to others? Etc.

Then we have a working solution there, just need to make sure that that GOGMix stays near the top. Adding Linux to an existing Windows installation is pretty simple. They'd need like 3 major distros, all of which are free and can be installed alongsie Windows. Mac support on the other hand would necessisate acquisition of new hardware, and that would be costly. How hard can it be to find a Linux guy wanting to get more games officially on Linux and living currently in Warsaw? I know at least one that fits the bill (I would include myself, but my master's degree takes up a lot of my time). If that would be the case then it's better not to try it at all, as that would require Wine. DOSBox is pretty reliable and stable from my experience. Wine is not, with notable regressions in each update (it's usually 2 steps forward, 1 back). I admit that Linux users have the least to gain. But then there are Mac users. While on Linux wine seems to be pretty widespread, I don't think that's the case with Wine on intel Macs. Also, amongst Mac users there are those that have the G4/G5 hardware. You can't run any windows executables on those (There was a project called Darwine that was supposed to combine Qemu with wine. It would emulate x86 hardware and run wine on it. It still doesn't work). I know personally the pain - my Linux/Windows laptop got damaged lately and I'm stuck with a G5 Powermac. It's fully capable of running DOSBox at reasonable speeds, but I have no way of installing the games.