And what the purpose of those serials ?

When you register those keys on the Paradox forum it gives you full access to the sub-forum of the respective games (which means the modding threads etc.)

For Paradox games, the serials are necessary for registration in the respective subforum in Paradox's site.

Ah, i was thinking something like that , but thanks for the confirmation :)

Well , mandatory to play or not ? (i think if it was the case there were already lots of screams :p), because now both of you lost me ^_^

Yeah, me too! Pity that I got the native Linux version from Humble first, in the last Humble Indie Bundle. But still, I'm glad I've been able to remove my custom NON-LINUX tag from it in my GOG library. :)

I see. Then, I have included all the Paradox games that come with serials (Cities in Motion, Europa Universalis III, Europa Universalis: Rome, Hearts of Iron III and Majesty 2) in my list/mix. Thanks for the confirmation.

Same here. Not sure if EU I+II, HoI I and Majesty (because Paradox is not the original publisher) ever had serials but Victoria Revolutions, Crusader Kings Deus Vult and Hearts of Iron 2 Doomsday Armageddon definitely have serials elsewehere (just checked it) which means that the Complete Editions of those games should also get serials here.
You're welcome.

It's not mandatory - one just won't have access to that parts of the forum.

No, not mandatory at all. It's just that without them, you can't access certain parts of Paradox's respective subforum.

for the records :

victoria would probably get a serial (i have it on steam , and it has one)

crusader kings , majesty gold (others i have aswell there) don't have one, so they are probably too old.

That's what i was thinking so....thanks !

Interesting. Crusader Kings (or its Addon Deus Vult to be specific) has a serial on GamersGate

Well on Steam its the complete version , so...that's odd o.O

Possibly they dropped the serial with the complete version... i don't know.

Odd...indeed, especially since Victoria has one on Steam and it also should be the complete version although named after the Addon....
Well in that case we might not get a serial here because it's also the complete version here....

On the other hand Crusader Kings 1 was released on Steam years after it was released on GamersGate. That might explain the differences.

Victoria Revolutions = Victoria Complete (paradox & their bloody names :S), i just checked the complete package of Victoria 1 + 2

That's what i thought....not having serials for Crusader Kings Complete doesn't make any sense then....

Edit: Actually it doesn't matter - even without the serial you have full access to the respective subforum.
Which makes serials for those older games pretty irrelevant. Knowing that i doubt we will get any serials for the Paradox games currently missing them.