• Facebook MAUs (Q3 2023): 3.05B
• Youtube MAUs (2024): 2.49B
• Snapchat MAUs (2024): 750M
• ChatGPT users: 200M(?)
• addresses that have sent/received on Tron: 211M
• total UTXO set size on Bitcoin: 209M
• addresses that have sent an tx on Ethereum: 185M
• Binance all time users: 176M
• Coinbase registered users (2022): 100M
• Chase customers registered (2024): 80M
• signers on Solana: 35.6M(?)
• Robinhood registered users (2022): 15.9M
• addresses that have sent a tx on Arbitrum: 13.9M
• addresses that have swapped on Uniswap across any chain: 10.2M
• addresses that have sent at tx on Optimism: 6.8M
• addresses that have sent a tx on Base: 3.4M
• addresses that have swapped via Jup (this is an undercount but query too slow): 2.4M

Addresses and registered users are not at all the same. says nothing about the quality of usage or retention or anything like that. That being said, raw numbers are still good to keep as a benchmark.