Honestly there is too much that would need to be included to make a simple list but I'll try.

1) Basic networking principles, VPNs, TOR, Dns resolvers, BTC, XMR, browser protections (like fingerprinting, auto cookie deletion, false profile randomizers, etc), self sovereignty through self hosting, what OS' to use and avoid (ie Windows vs Linux vs Unraid), sandboxing information with VMs or Unraid and so much more

2) Absolutely nothing. If I want to avoid it I would include how to avoid it.

3) No idea as I do not read newsletters usually.