Jeffludwig.com is a GOG.com affiliate
You're here because you're curious about this thing called GOG.com. You've got questions, and hopefully I've got the answers you're looking for. Of course, feel free to ask any other questions on your mind.
Who is GOG.com?
If you haven't heard about GOG.com, you should 
. Originally called "Good Old Games", this is a site that is created by gamers, and exists for gamers. They cultivate relationships with the companies that originally developed old classic games (as well as new "Indie" developers who are creating new content), and release their games DRM-free for modern Windows OSes. GOG is committed to delivering the best products possible, and works with content developers to offer "freebies" and bonus content (such as game maps, soundtracks, etc.)
You can read a recent press release showcasing GOG.com here.
What do you mean, DRM-free?
GOG.com explains it like this: "It basically means that you actually own the games bought at GOG.com. Once you download a game, you can install it on any PC and re-download it whenever you want, as many times as you need."
Why are you linking to GOG.com?
The dark side of DRM.
Primarily, because I believe in their company and the things they stand for. I believe that removing DRM from purchased media is the best way to combat piracy, because (briefly) saavy people will always find a way to defeat these measures, and when that happens, the DRM-protected products stand to suffer financial losses. Apparently, Steve Jobs agreed. I believe that companies that employ these measures are shooting themselves in the financial foot, and I want to see companies that make successful products succeed and make money. I think this can be facilitated by licensors treating consumers as good people— not criminals— and by releasing products that are not "Defective by Design". I also think that things like this must be stopped.
Convenience for you
Secondarily, because GOG sells games that have been featured and/or modded here at jeffludwig.com. It is an easy way for me to help people to find DOS/Windows based games, in case they are interested in playing my mods, but haven't bought the games (or lost them over the years).
You can support Jeffludwig.com!
Finally, in the interest of full disclosure, I recently became an affiliate of GOG.com. That essentially means that I advertise for them. You can help support jeffludwig.com by clicking on a link to GOG.com from this site, signing up, and purchasing merchandise.
Why would I want to do this?
Don't you like my site? 
All kidding aside, I make no money for doing all the things presented here on this site. If you value what I do, you can help in a tangible way to keep the site online, and promote future mods.
Also, I hear rumors that there are special perks for people who are referred to GOG.com from their affiliates...
All right, you've convinced me. How do I sign up?
On the top of every page, there's a little button that says "DRM-free PC Classics GOG.com". You can click that. However, that takes scrolling the window. I'll make it easy on you, and provide another link on the right of this answer. Thanks again!