I just noticed this today. Maybe it's just a coincidence, because it's all part of their D&D sales series, but GOG.com has put nearly every game mentioned in the Project Eternity video (except Arcanum & the Fallouts, I think) up for sale.
In the wake of the Project Eternity getting a million dollars in a single day, I think there are a lot of people out there thinking about these titles and interested parties who never played most of them who want to see what all the excitement is about.
This was either a really smart move on their part or an incredibly lucky coincidence. Either way, I suspect they'll sell a lot of games this week.
Just in case anyone thinks this is spam, I have zero affiliation with GOG.com or Obsidian other than buying and liking games from both.