[pipermerriam]

At present, as far as I know all of the scalability plans for Ethereum are theoretical. That said the plan thus far is:

Light Client Support allows for running a node that does not sync the full chain, but rather downloads and verifies only the small parts necessary to send transactions and read state.

Proof-of-Stake replaces Proof-of-Work which opens up options for things like parallelization.

Sharding is a plan to split the blockchain into many smaller chains that are all linked but operate largely independently, allowing for horizontal scaling of the network. Transactions within a shard are synchronous. Transactions across shards are asynchronous.