NIP-54
======

Topical Notes
-------------

`draft` `optional`

This NIP enables authors to post exclusively into topics, without polluting their main feed. Authors can post to locations, hashtags, labels, and urls in a way that only followers of those topics will receive their posts. 

## Topical Note Kind

Kind `21` defines a `kind:1`-equivalent event that MUST NOT be displayed unless the user follows one of the `g`, `t`, `r` or `l` tags. 

```jsonc
{
  "kind": 21,
  "tags": [
    ["g", "<geohash>"],
    ["t", "<hashtag>"],
    ["r", "<url>"],
    //.. 
    ["L", "<label namespace>"],
    ["l", "<label>", "<label namespace>"],
  ],
  "content": "This is a note for followers of the hashtag, location OR url. My followers should not see this.",
  //...
}
```

`.content` MUST be plain text and tags that mention, quote and assemble threading structures MUST follow [NIP-10](10.md).

## Topical Relay Setup

Kind `30021` defines a topic follower. It registers a list of relays to aggregate events for each topic. 

The `d` tag of this kind is equal to `name:value` of the topics used in kind `21`. 

```js
{
  "kind": 30021,
  "tags": [
    ["d", "g:<my city's geohash>"],
    ["r", "wss://my-city-owned-relay"],
    ["r", "wss://independent-but-city-based-relay"],
    // ... other tags
    ["title", "Name of this topic"]
  ],
  "content": nip44Encrypt([
    ["r", "wss://my-city-owned-relay2"], // private relay
    ["title", "Name of this topic"] // private topic title
    // ... other tags
  ]),
  //...other fields
}
```

The `.content` contains a list of private tags.

Clients MUST seek and broadcast events from and to the relays defined for each topic.