Bitchat’s Geohash channels are open, permissionless chatrooms where anyone can participate and send messages. This is similar to how any Bitcoiner can send a Bitcoin transaction. However, open, permissionless systems are especially prone to spam. Because Bitcoin’s block size is limited, transactions must bid for inclusion, and only those that pay sufficient fees are included in blocks, so senders cannot spam. If open, permissionless real-time chatrooms are as indispensable as open, permissionless monetary payment systems, we can expect them to evolve a fee mechanism.