Retro Gamer Magazine did an article on GoG back when it was still in the beta and the focus was on classics.

So I had a friend who is a heavy PC player. I was semi complaining how it would be nice to play old games like 7th Guest on modern systems. I was a console gamer in my early days of electronic gaming and missed out on a lot of old PC games (I had nothing against PC's, rather I lacked money for consoles and PC's as a child). He mentioned to me casually that GOG had a lot of old PC games for sale that are done to work on modern OS's. The occasional sales and old games had me hooked for about 6 months. In that span I must have bought 76 games. Funny thing, my buddy has never bought a game from this site. In fact he has no desire to play old games (unless the game is extremely compelling and he hasn't played).

Personally, I found this great site after reading somewhere on the Internet that Treasure Adventure was available for free on GOG with extras that weren't available-as I found out- on the developer's site (I thought I read it on kotaku, but I can't find anything related right now). Thus I subscribed on GOG on May 2013 (as stated on my profile-actually it was on the 31st of May, as it says on my account's freebies; if I had subscribed one day later, it would say Jun 2013) - and because I subscribed initially for that game my nickname is the one you can see (Treasure). At any rate, I liked Treasure Adventure but got stuck early in the game, so I left it. However, I found out there are many more nice games on this site, so I stayed and eventually started buying and playing games from GOG (as I appreciate the fact that all the games I bought till now run on my system hassle-free).

My little sister gifted me a GOG code for Creatures Exodus.

I got the urge to play Cannon Fodder again and decided to pirate it because I thought it was abandonware anyway. Turned out that it wasn't.

I was just googling for some baba magic services, and...

Looking for how to run POD on a modern PC.

... and then your marriage specialist told you about this site. I know this story very well...

I actually found Gog through abandondware sites as I was scouring them for old games that I had missed. I just couldn't afford those games on sites like Amazon (100+ for functioning copies of some of the games), so when Gog popped up and offered me DRM-free games that were already tweaked to work on modern computers, all for the price of $9.99 or less, I was sold.

I've never pirated a game since.

In my dreams an angle entered took my hand and whisked me to this site..oh and the Star Wars melody was playing.
Now that was the Hollywood version...the truth is somewhat more realistic:
Pure luck. I was searching for a patch for Fallout cause i wanted to play it again and didn't save it last time...sadly the link from NMA was broken..but google showed me the light.

I don't quite remember, but I read in some forum about a site where you can legally download some old games. I thought "neato", but didn't check it further (as I probably felt I already have more than enough old PC retail games).

Later I read about it again, I think when they started offering Witcher and/or Witcher 2 without DRM. I think that is when I finally checked out the site properly.

But I recall DotEmu was also related to that, I checked and joined DotEmu probably at the same time. They both seemed pretty good and at first I was unsure to which site I should bring my euros mostly, but GOG won me over because there was more life in the forum, and there were some newer games too on GOG (like the Witcher games). But I have a bunch of games on DotEmu too, and might even buy something there if they have something interesting not available for GOG. Thank god I bought Vampire: Bloodlines from there before it was pulled.

I really used to dig abandonware sites, and through my interest in oldies I started looking at GOG a few years back while it was still beta, but never registered until someday I saw they were selling Arcanum, which was my very first purchase here since it is a game I love deeply.

I learned about GoG through an article in Game iformer magazine. The article claimed that the site was a good place to find classic games. I had never finished Phantasmagoria so I came to see if it was here. Bought the game and stuck around for Fallout

It was indeed. For who else is more acquainted with eternity than Our Jack? We may not always see His Page Of Insomnia, but it is there, eternal, changeless, showing His Number which never decreaseth.

I believe I put something like "Planescape: Torment purchase online" on Google search, and then clicked one of the first links that appeared.