Mike Goldin also taught an Intro to Solidity Smart Contract Development and Truffle 4. I was quite happy to run into fellow members of the Oakland Blockchain Developers at the code labs.

In terms of big news in Ethereum, Joseph Poon spoke about Plasma on the Main Stage, which Vitalik Buterin has said is independent of, but strongly complementary to, Proof of Stake (PoS) and sharding. Plasma is a blockchain of nested blockchains, and is one solution to the scalability problem in blockchain. Similar to the Lightning Network, Plasma is a series of contracts which runs on top of a root blockchain, in this case the Mainnet Ethereum blockchain. Child blockchains can do an incredibly large amount of computations, while the root blockchain processes only a small amount, thereby making interactions less expensive and transactions faster. Parties are responsible for monitoring the chain in which they have interest - in most cases, one would not have to watch the full chain. In the case of an attack, participants can quickly and cheaply exit the child chain back to root. Some in the blockchain community, like OmiseGO, have already indicated they would use Plasma.