Cloud gaming is effectively impossible due to little things like the speed of light. Sure, you could play Civilization via cloud but good fucking luck with competitive shooters.

Would be cool to play civ5 on a long term server.

I’m thinking something that emails you when its your turn too. Like playing chess over mail.

Isn’t that a thing in freeciv, that open source version of civilization?
There is a freeciv? How did i not know this
Yeah, there’s a web version of the game if you want to try it out, though it seems to be based on civilization 2 or 3 rather than 5 or 6.
Unciv is based on civ5 and has support for BNW from the mod list.