Oddbean new post about login | logout You only need a client to publish a new event, and a relay to accept that event. Anyone connected to that relay, using a client with an interface to display the new event, will be able to see it. You can even have your own relay attached to a client; in that case, you don't need relays to accept your new event.
You're welcome to have your own island. Make a Jackson Pollock of an App, and do what you want. However, you're now responsible for any issues with the island and you're not going to have anyone else's support because you don't speak the common language.
That's where the "protocol" comes in; clients have agreed to index and broadcast events, such as notes, follow lists, and profile data, in a predetermined manner. This cooperation is between the client and relay, as they both follow the same protocol. Here's a fun fact: you can add "tags" to events, providing additional information. You can use this new tag info to create variations of the same kind of event, while other clients can choose to ignore it. Example of event structure. https://image.nostr.build/049ae86040c4bbb5ee2334310ed785ba9287d491b0520202493aaa0010925dfe.jpg#m=image%2Fjpeg&dim=1080x1902&blurhash=%5D384Sst%2B00%23UDiTLt7rqW%3DbFl.%252z%3BJ6IovfR*E%24xHxu%3DuX8ENr%3FspR%24WBs%3Bt6j%5DIns%3BxbNZbb.8n%2BRPX7NGrYNuNa%23%3Axa&x=c532b7722ace8e456f86a6496250858012dc3a735b4cd1fd705a9cfa8716e6c8
