This is still the best introduction to Nostr, IMO, as it perfectly captures why Nostr is so incredibly important, by showing what's wrong with the current social media landscape. 
nostr:nevent1qqs9gg4thq8ng87z8377jxksjwhk9dl0f8su9c4kq335ydzp0ykmv5gppemhxue69uhkummn9ekx7mp0qgs0ulmtcmmn8zmkh0uqmdqz4hn9j5lzpvhj8enw3xpqfd3ucsjnngcrqsqqqqqpn792fg