SegWit Addresses: SegWit (Segregated Witness) is a protocol upgrade that changes the way data is stored. There are different types of SegWit addresses: legacy, P2SH, and Bech32. Legacy addresses start with a 1 and are not SegWit-enabled. P2SH addresses start with a 3 and can be a variety of things, including SegWit scripts. Bech32 addresses start with bc1 and are the ultimate goal as they are native SegWit addresses. The choice between these depends on the audience you're dealing with and their wallet capabilities.

Schnorr Signatures: Schnorr signatures are a proposed change to Bitcoin that would improve the scalability and privacy of the network. They are shorter than the current ECDSA signatures, which would save space on the blockchain. They also allow for signature aggregation, which could further reduce the space used by transactions. The space gain from Schnorr signatures could be between 15% to 60% or more, depending on how they are applied.

Taproot: Taproot is a proposed Bitcoin protocol upgrade that would increase Bitcoin's privacy and efficiency. It makes all transactions look the same to outside observers, making it harder to distinguish between different types of transactions. This would increase privacy as it would be harder to track specific transactions. Taproot is not a direct privacy solution like zero-knowledge proofs, but an indirect solution that allows for other privacy-enhancing techniques.

Graftroot: Graftroot is another proposed Bitcoin protocol upgrade related to Taproot. It wasn't discussed in detail in this video.

Privacy and Future Upgrades: Andreas emphasizes that while these upgrades will improve privacy, they will not make Bitcoin completely anonymous. Privacy is an ongoing battle, and as attacks against privacy become more sophisticated, the technology to protect privacy must also evolve. He expects pushback against strong privacy in Bitcoin, but believes it's a battle that needs to be won.