To celebrate reaching 500k members on Paradox Plaza, Paradox gave out a steam code for EU3 Chronicles to everyone subscribed to the newsletter. They've also opened a webshop
here, and until Feb 17th, they'll have a sale with some of their games at 50% off.
EDIT: I just realized this is a pretty big change; previous game giveaways were really only on Gamersgate. In addition, the Paradox Webshop sells Steam keys. I suppose its to be expected, as Paradox has been aligning itself with Steam recently (such as the announcement EU4 will be Steam-only).