1 files changed, 29 insertions, 12 deletions

diff --git a/25.md b/25.md
index 3b4aa59..671c55f 100644
--- a/25.md
+++ b/25.md
@@ -25,24 +25,22 @@ consider it a "+".
 Tags
 ----
 
-The reaction event SHOULD include `e` and `p` tags from the note the user is
-reacting to. This allows users to be notified of reactions to posts they were
-mentioned in. Including the `e` tags enables clients to pull all the reactions
-associated with individual posts or all the posts in a thread.
+The reaction event SHOULD include `e` and `p` tags from the note the user is reacting to (and optionally `a` tags if the target is a replaceable event). This allows users to be notified of reactions to posts they were mentioned in. Including the `e` tags enables clients to pull all the reactions associated with individual posts or all the posts in a thread. `a` tags enables clients to seek reactions for all versions of a replaceable event.
 
-The last `e` tag MUST be the `id` of the note that is being reacted to. 
+The last `e` tag MUST be the `id` of the note that is being reacted to.
 
 The last `p` tag MUST be the `pubkey` of the event being reacted to.
 
-The reaction event MAY include a `k` tag with the stringified kind number
-of the reacted event as its value.
+The `a` tag MUST contain the coordinates (`kind:pubkey:d-tag`) of the replaceable being reacted to.
+
+The reaction event MAY include a `k` tag with the stringified kind number of the reacted event as its value.
 
 Example code
 
 ```swift
 func make_like_event(pubkey: String, privkey: String, liked: NostrEvent) -> NostrEvent {
-    var tags: [[String]] = liked.tags.filter { 
-        tag in tag.count >= 2 && (tag[0] == "e" || tag[0] == "p") 
+    var tags: [[String]] = liked.tags.filter {
+        tag in tag.count >= 2 && (tag[0] == "e" || tag[0] == "p")
     }
     tags.append(["e", liked.id])
     tags.append(["p", liked.pubkey])
@@ -54,6 +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.
+
+```jsonc
+{
+  "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
 ---------------------
 
@@ -61,15 +79,14 @@ The client may specify a custom emoji ([NIP-30](30.md)) `:shortcode:` in the
 reaction content. The client should refer to the emoji tag and render the
 content as an emoji if shortcode is specified.
 
-```json
+```jsonc
 {
   "kind": 7,
   "content": ":soapbox:",
   "tags": [
     ["emoji", "soapbox", "https://gleasonator.com/emoji/Gleasonator/soapbox.png"]
   ],
-  "pubkey": "79c2cae114ea28a981e7559b4fe7854a473521a8d22a66bbab9fa248eb820ff6",
-  "created_at": 1682790000
+  // other fields...
 }
 ```