diff --git a/25.md b/25.md
index 17c203e1..f0386034 100644
--- a/25.md
+++ b/25.md
@@ -52,6 +52,26 @@ func make_like_event(pubkey: String, privkey: String, liked: NostrEvent) -> Nost
 }
 ```
 
+Reactions to a website
+---------------------
+
+If the target of the reaction is a website, the reaction MUST be a `kind 17` event and MUST include an `r` tag with the website's URL.
+
+```json
+{
+  "kind": 17,
+  "content": "⭐",
+  "tags": [
+    ["r", "https://example.com/"]
+  ],
+  ...other fields
+}
+```
+
+URLs SHOULD be [normalized](https://datatracker.ietf.org/doc/html/rfc3986#section-6), so that reactions to the same website are not omitted from queries.
+A fragment MAY be attached to the URL, to react to a section of the page.
+It should be noted that a URL with a fragment is not considered to be the same URL as the original.
+
 Custom Emoji Reaction
 ---------------------
 
diff --git a/README.md b/README.md
index 6c83ba88..d6840fcd 100644
--- a/README.md
+++ b/README.md
@@ -109,6 +109,7 @@ They exist to document what may be implemented by [Nostr](https://github.com/nos
 | `13`          | Seal                            | [59](59.md)                            |
 | `14`          | Direct Message                  | [17](17.md)                            |
 | `16`          | Generic Repost                  | [18](18.md)                            |
+| `17`          | Reaction to a website           | [25](25.md)                            |
 | `40`          | Channel Creation                | [28](28.md)                            |
 | `41`          | Channel Metadata                | [28](28.md)                            |
 | `42`          | Channel Message                 | [28](28.md)                            |
@@ -245,7 +246,7 @@ They exist to document what may be implemented by [Nostr](https://github.com/nos
 | `L`               | label namespace                      | --                              | [32](32.md)                           |
 | `m`               | MIME type                            | --                              | [94](94.md)                           |
 | `q`               | event id (hex)                       | relay URL                       | [18](18.md)                           |
-| `r`               | a reference (URL, etc)               | petname                         | [24](24.md)                           |
+| `r`               | a reference (URL, etc)               | --                              | [24](24.md), [25](25.md)              |
 | `r`               | relay url                            | marker                          | [65](65.md)                           |
 | `t`               | hashtag                              | --                              |                                       |
 | `alt`             | summary                              | --                              | [31](31.md)                           |