Pemptus: Jeff refused to put his games up on Steam for a long time. He refused to reduce the price of his games on his own website for a long time. This despite the evidence that he'd likely sell more games and make more money.
The list of possible reasons why games don't appear on here isn't just fanboyism at work.
keeveek: and he decided to relaese all of his more modern games on steam at once, but not on GOG , because...?
Feel like correcting this.
http://store.steampowered.com/app/112100/
Look at the release date, unlike GOG Steam puts the "Steam Release Date" (should be obvious on later games). Avadon The Black Fortress has Aug. 17th 2011.
http://store.steampowered.com/sub/12171/
Geneforge Saga, Nov 2, 2011 two an a half months later than Avadon(this is where it should be obvious, unless ya know, that whole series came out less than a year ago Edit: The individual games do show actual release dates, the Saga shows the SRD).
http://store.steampowered.com/app/208400/
Avernum Escape From the Pit. April 11, 2012 5 months later.
http://store.steampowered.com/sub/14583/
Avernum Bundle May 11, 2012. 1 month later.
So unless those dates are inaccurate, all of his games did not come out on Steam all at once. Based on that I am leaning towards Spiderweb Software being the reason that the rest of the games are not on GOG. Could very well be wrong though, GOG may have everything in place to sell them and just not want to release them, but seeing as how the games were sprinkled out on Steam I could see how Spiderweb may want them sprinkled out on GOG also.