1 files changed, 105 insertions, 15 deletions

diff --git a/51.md b/51.md
index b184f42..d113f80 100644
--- a/51.md
+++ b/51.md
@@ -6,35 +6,64 @@ Lists
 
 `draft` `optional` `author:fiatjaf` `author:arcbtc` `author:monlovesmango` `author:eskema` `author:gzuuus`
 
-This NIP defines lists of things that users can create. Lists can contain references to anything, and these references can be **public** or **private**.
+This NIP defines lists of things that users can create. Lists can contain references to anything, and these
+references can be **public** or **private**.
 
-Public items in a list are specified in the event `tags` array, while private items are specified in a JSON array that mimics the structure of the event `tags` array, but stringified and encrypted using the same scheme from [NIP-04](04.md) (the shared key is computed using the author's public and private key) and stored in the `.content`.
+Public items in a list are specified in the event `tags` array, while private items are specified in a JSON
+array that mimics the structure of the event `tags` array, but stringified and encrypted using the same
+scheme from [NIP-04](04.md) (the shared key is computed using the author's public and private key) and
+stored in the `.content`.
 
-## Generic lists
+## Types of lists
 
-The kinds `30000` and `30001` have been reserved for generic lists. These must be accompanied by a `d` tag identifying the list, but these are generally client-specific, except in the standard cases specified below.
+### Generic lists
 
-### Standard lists
+The kind `30001` has been reserved for generic lists. These must be accompanied by a `d` tag identifying the
+list, but these have no standard meaning and are generally client-specific (except in the standard cases
+specified below).
 
-These are some standards that emerged in the wild:
+## Standard lists
+
+Users are expected to have a single list of each of these types. They have special meaning and clients may
+rely on them to augment the user profile or browsing experience.
+
+For example, _mute lists_ can contain the public keys of spammers and bad actors users don't want to see in
+their feeds or receive annoying notifications from.
 
 | name             | kind  | "d" tag         | description                                               | expected tag items                                |
 | ---              | ---   | ---             | ---                                                       | ---                                               |
-| Mute list        | 30000 | `"mute"`        | things the user doesn't want to see in their feeds        | `"p"` (pubkeys), `"t"` (hashtags)                 |
+| Mute list        | 10000 |                 | things the user doesn't want to see in their feeds        | `"p"` (pubkeys), `"t"` (hashtags)                 |
 | Bookmarks list   | 30001 | `"bookmark"`    | things the user intends to save for the future            | `"e"` (kind:1 notes), `"a"` (kind:30023 articles) |
 | Pin list         | 30001 | `"pin"`         | events the user intends to showcase in their profile page | `"e"` (kind:1 notes)                              |
 | Communities list | 30001 | `"communities"` | [NIP-72](72.md) communities the user belongs to           | `"a"` (kind:34550 community definitions)          |
 
 ## Sets
 
-Sets are lists with well-defined meaning and purpose and user-assigned `d` tags meant to be displayed in the UI. For example, _relay sets_ can be displayed in a dropdown UI to give users the option to switch to which relays they will publish an event or from which relays they will read the replies to an event; or _curation sets_ can be used by apps to showcase curations made by others tagged to different topics.
+Sets are lists with well-defined meaning that can enhance the functionality and the UI of clients that rely
+on them. Unlike standard lists, users are expected to have more than one set of each kind, therefore each of
+them must be assigned a different `"d"` identifier.
+
+For example, _relay sets_ can be displayed in a dropdown UI to give users the option to switch to which
+relays they will publish an event or from which relays they will read the replies to an event; _curation sets_
+can be used by apps to showcase curations made by others tagged to different topics.
+
+Aside from their main identifier, the `"d"` tag, sets can optionally have a `"title"`, an `"image"` and a
+`"description"` tag that can be used to enhance their UI.
+
+| name                  | kind  | description                                                                                   | expected tag items                                |
+| ---                   | ---   | ---                                                                                           | ---                                               |
+| Relay sets            | 30002 | user-defined relay groups the user can easily pick and choose from during variadic operations | `"relay"` (relay URLs)                            |
+| Article Curation sets | 30004 | groups of articles picked by users as interesting and/or belonging to the same category       | `"a"` (kind:30023 articles), `"e"` (kind:1 notes) |
+
+## Deprecated standard lists
 
-Aside from their main identifier, the `"d"` tag, sets can optionally have a `"title"`, an `"image"` and a `"description"` tag that can be used to enhance their UI.
+Some clients have used these lists in the past, but they should work on transitioning to the [standard formats](#standard-lists) above:
 
-| name                  | kind  | description                                                                                   | expected tag items          |
-| ---                   | ---   | ---                                                                                           | ---                         |
-| Relay sets            | 30002 | user-defined relay groups the user can easily pick and choose from during variadic operations | `"relay"` (relay URLs)      |
-| Article Curation sets | 30003 | groups of articles picked by users as interesting and/or belonging to the same category       | `"a"` (kind:30023 articles) |
+- kind:30000 and `d` "mute"
+
+| kind  | "d" tag  | use instead            |
+| ---   | ---      | ---                    |
+| 30000 | `"mute"` | kind 10000 _mute list_ |
 
 ## Examples
 
@@ -45,9 +74,8 @@ Aside from their main identifier, the `"d"` tag, sets can optionally have a `"ti
   "id": "a92a316b75e44cfdc19986c634049158d4206fcc0b7b9c7ccbcdabe28beebcd0",
   "pubkey": "854043ae8f1f97430ca8c1f1a090bdde6488bd5115c7a45307a2a212750ae4cb",
   "created_at": 1699597889,
-  "kind": 30000,
+  "kind": 10000,
   "tags": [
-    ["d", "mute"],
     ["p", "07caba282f76441955b695551c3c5c742e5b9202a3784780f8086fdcdc1da3a9"],
     ["p", "a55c15f5e41d5aebd236eca5e0142789c5385703f1a7485aa4b38d94fd18dcc4"]
   ],
@@ -56,6 +84,68 @@ Aside from their main identifier, the `"d"` tag, sets can optionally have a `"ti
 }
 ```
 
+### A _communities list_ with just public items
+
+```json
+{
+  "id": "da6b18c5452b5a60bf49588fc13ae4d1a047519c13e49a77b3184e6188c7bb1c",
+  "pubkey": "83fd07de9b763334cc9d46f2785c2558e6c2eabfe7d0c6ec214667cbaec50d47",
+  "created_at": 1689082210,
+  "kind": 30001,
+  "tags": [
+    [
+      "d",
+      "communities"
+    ],
+    [
+      "a",
+      "34550:83fd07de9b763334cc9d46f2785c2558e6c2eabfe7d0c6ec214667cbaec50d47:meme"
+    ],
+    [
+      "a",
+      "34550:b9a537523bba2fcdae857d90d8a760de4f2139c9f90d986f747ce7d0ec0d173d:NoBullshitBitcoin"
+    ]
+  ],
+  "content": "",
+  "sig": "e400cc8bf24955243137e4456b22142fdff400a7950cf0b0ac2ee86ed78671e2fddf9a9b40c77ccf8397f9c21d608b3fab3678ff13713fc3f97a4394cf766079"
+}
+```
+
+### A _curation set_ of articles and notes about yaks
+
+```
+{
+  "id": "567b41fc9060c758c4216fe5f8d3df7c57daad7ae757fa4606f0c39d4dd220ef",
+  "pubkey": "d6dc95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c",
+  "created_at": 1695327657,
+  "kind": 30004,
+  "tags": [
+    [
+      "d",
+      "jvdy9i4"
+    ],
+    [
+      "title",
+      "Yaks"
+    ],
+    [
+      "summary",
+      "The domestic yak, also known as the Tartary ox, grunting ox, or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Gilgit-Baltistan, Tajikistan and as far north as Mongolia and Siberia."
+    ],
+    [
+      "image",
+      "https://cdn.britannica.com/40/188540-050-9AC748DE/Yak-Himalayas-Nepal.jpg"
+    ],
+    ["a", "30023:26dc95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:95ODQzw3ajNoZ8SyMDOzQ"],
+    ["a", "30023:54af95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:1-MYP8dAhramH9J5gJWKx"],
+    ["a", "30023:f8fe95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:D2Tbd38bGrFvU0bIbvSMt"],
+    ["e", "d78ba0d5dce22bfff9db0a9e996c9ef27e2c91051de0c4e1da340e0326b4941e"]
+  ],
+  "content": "",
+  "sig": "a9a4e2192eede77e6c9d24ddfab95ba3ff7c03fbd07ad011fff245abea431fb4d3787c2d04aad001cb039cb8de91d83ce30e9a94f82ac3c5a2372aa1294a96bd"
+}
+```
+
 ## Encryption process pseudocode
 
 ```scala