Imagine you have a bunch of toy blocks, and you want to share them with your friend who lives far away. You tell the service what blocks you want to send or rec

Imagine you have a bunch of toy blocks, and you want to share them with your friend who lives far away. You tell the service what blocks you want to send or receive (like "I want all the red blocks!") The service tells you where to get your blocks from, kind of like getting a treasure map. Get blocks from your friend (like receiving a gift), Send blocks to your friend (like giving a gift), Trade blocks back and forth (like playing together) Is really fast (like a super-speedy delivery truck) and can handle lots and lots of blocks at once Makes sure only your friends can see your blocks (using special secret passwords) Can tell you if something goes wrong (like if some blocks got lost)