Ask HN: Multiplayer games between iOS and Android

I am trying to get a better understanding of how do the - turn based asynchronous games - like Words with friends etc. work?

Can any one please recommend a site or documentation that can help me understand them better? the design part not the how-to-play part :)

I want to learn more about how to design (and maybe develop) a game but am having a tough time trying to get started and to find information. Googling information comes up with a whole lot of cheats and how to play the games but that's not what I want. I want to learn and understand the design and technical aspects of how it is done.

Any pointers or help is really appreciated. Anything that can help me get started will be useful :)