As the sibling comment said, you do the same way you scale anything else: add more servers that replicate the same data. As it becomes to large, shard your publ

As the sibling comment said, you do the same way you scale anything else: add more servers that replicate the same data. As it becomes to large, shard your publications depending on type. Meteor's livequery works better serving a lot of similar subscriptions, so at some point you can have multiple server types each taking care of one scope.