One of the big things about building games is storing your creation and for me that is cloud integration.
I'm using Azure's Table Storage service. Every time a player builds or destroys a block, it gets added into the cloud. When the player restarts, it gets restored from the cloud.
This might not seem very efficient, but it has a level of robustness built in. In the even of an cloud outage like the one that happened in Sydney a few weeks ago, at worst the player will need to rebuild a little bit. If the game had been saved as a blob, the player could have lost the entire session's work or even worse their entire world. To improve efficiency the plan is to run a job each night to consolidate the changes into a compressed zip payload.
Of course this tech is multiplayer aware, so it is actually the listening server that gets and sends data to and from the cloud and spreads it out to all the players.
My daughter made this 'house' kind of looks more like a bunker. But she is having fun. Unknown to me, she has invited her mates over next Friday to give it a go - no pressure!