diff --git a/docs/roadmap.md b/docs/roadmap.md
index 6ee830c..5ee5ba1 100644
--- a/docs/roadmap.md
+++ b/docs/roadmap.md
@@ -33,7 +33,7 @@
   - [ ] Posts
     - [x] New
     - [x] Reply
-    - [x] Reply all
+    - [x] Comment
     - [ ] Pre-publish preview
     - [ ] Add blob attachment(s)
     - [x] Correctly set `branch`
diff --git a/src/app.js b/src/app.js
index 1b880b8..46883b0 100644
--- a/src/app.js
+++ b/src/app.js
@@ -23,9 +23,9 @@ const likesPage = require('./pages/likes')
 const meta = require('./pages/meta')
 const mentions = require('./pages/mentions')
 const reply = require('./pages/reply')
-const replyAll = require('./pages/reply-all')
+const comment = require('./pages/comment')
 const publishReply = require('./pages/publish-reply')
-const publishReplyAll = require('./pages/publish-reply-all')
+const publishComment = require('./pages/publish-comment')
 const image = require('./pages/image')
 const blob = require('./pages/blob')
 const publish = require('./pages/publish')
@@ -189,9 +189,9 @@ module.exports = (config) => {
       const { message } = ctx.params
       ctx.body = await reply(message)
     })
-    .get('/reply-all/:message', async (ctx) => {
+    .get('/comment/:message', async (ctx) => {
       const { message } = ctx.params
-      ctx.body = await replyAll(message)
+      ctx.body = await comment(message)
     })
     .post('/reply/:message', koaBody(), async (ctx) => {
       const { message } = ctx.params
@@ -199,10 +199,10 @@ module.exports = (config) => {
       ctx.body = await publishReply({ message, text })
       ctx.redirect(`/thread/${encodeURIComponent(message)}`)
     })
-    .post('/reply-all/:message', koaBody(), async (ctx) => {
+    .post('/comment/:message', koaBody(), async (ctx) => {
       const { message } = ctx.params
       const text = String(ctx.request.body.text)
-      ctx.body = await publishReplyAll({ message, text })
+      ctx.body = await publishComment({ message, text })
       ctx.redirect(`/thread/${encodeURIComponent(message)}`)
     })
     .post('/publish/', koaBody(), async (ctx) => {
diff --git a/src/pages/comment.js b/src/pages/comment.js
new file mode 100644
index 0000000..17b2994
--- /dev/null
+++ b/src/pages/comment.js
@@ -0,0 +1,26 @@
+'use strict'
+
+const post = require('./models/post')
+const meta = require('./models/meta')
+const commentView = require('./views/comment')
+const ssbRef = require('ssb-ref')
+
+module.exports = async function commentPage (parentId) {
+  const parentMessage = await post.get(parentId)
+  const myFeedId = await meta.myFeedId()
+
+  const hasRoot = typeof parentMessage.value.content.root === 'string' && ssbRef.isMsg(parentMessage.value.content.root)
+  const hasFork = typeof parentMessage.value.content.fork === 'string' && ssbRef.isMsg(parentMessage.value.content.fork)
+
+  const rootMessage = hasRoot
+    ? hasFork
+      ? parentMessage
+      : await post.get(parentMessage.value.content.root)
+    : parentMessage
+
+  const messages = await post.threadReplies(rootMessage.key)
+
+  messages.push(rootMessage)
+
+  return commentView({ messages, myFeedId, parentMessage })
+}
diff --git a/src/pages/models/post.js b/src/pages/models/post.js
index c2df2a0..3965042 100644
--- a/src/pages/models/post.js
+++ b/src/pages/models/post.js
@@ -150,11 +150,15 @@ const transform = (ssb, messages, myFeedId) =>
       url: avatarUrl
     })
 
-    if (isRoot(msg)) {
+    const isPost = lodash.get(msg, 'value.content.type') === 'post' && lodash.get(msg, 'value.content.text') != null
+    const hasRoot = lodash.get(msg, 'value.content.root') != null
+    const hasFork = lodash.get(msg, 'value.content.fork') != null
+
+    if (isPost && hasRoot === false && hasFork === false) {
       lodash.set(msg, 'value.meta.postType', 'post')
-    } else if (isReply(msg)) {
-      lodash.set(msg, 'value.meta.postType', 'replyAll')
-    } else if (isNestedReply(msg)) {
+    } else if (isPost && hasRoot && hasFork === false) {
+      lodash.set(msg, 'value.meta.postType', 'comment')
+    } else if (isPost && hasRoot && hasFork) {
       lodash.set(msg, 'value.meta.postType', 'reply')
     } else {
       lodash.set(msg, 'value.meta.postType', 'mystery')
@@ -232,7 +236,7 @@ const post = {
 
     return messages
   },
-  fromRoot: async (rootId, customOptions = {}) => {
+  threadReplies: async (rootId, customOptions = {}) => {
     const ssb = await cooler.connect()
 
     const myFeedId = ssb.id
@@ -248,11 +252,11 @@ const post = {
       customOptions,
       ssb,
       query,
-      filter: (msg) => msg.value.content.root === rootId
+      filter: (msg) =>
+        msg.value.content.root === rootId &&
+        msg.value.content.fork == null
     })
 
-    console.log(messages)
-
     return messages
   },
   likes: async ({ feed }, customOptions = {}) => {
@@ -692,16 +696,23 @@ const post = {
 
     return post.publish(message)
   },
-  replyAll: async ({ parent, message }) => {
-    const fork = parent.key
-    const root = lodash.get(parent, 'value.content.root', parent.key)
-    message.root = fork || root
+  comment: async ({ parent, message }) => {
+    // Set `root` to `parent`'s root.
+    // If `parent` doesn't have a root, use the parent's key.
+    // If `parent` has a fork, you must use the parent's key.
+    const parentKey = parent.key
+    const parentFork = lodash.get(parent, 'value.content.fork')
+    const parentRoot = lodash.get(parent, 'value.content.root', parentKey)
+
+    const parentHasFork = parentFork != null
+
+    message.root = parentHasFork ? parentKey : parentRoot
     message.branch = await post.branch({ root: parent.key })
     message.type = 'post' // redundant but used for validation
 
     if (isReply(message) !== true) {
       const messageString = JSON.stringify(message, null, 2)
-      throw new Error(`message should be valid replyAll: ${messageString}`)
+      throw new Error(`message should be valid comment: ${messageString}`)
     }
 
     return post.publish(message)
diff --git a/src/pages/publish-reply-all.js b/src/pages/publish-comment.js
similarity index 79%
rename from src/pages/publish-reply-all.js
rename to src/pages/publish-comment.js
index 196b67d..ffe7b7b 100644
--- a/src/pages/publish-reply-all.js
+++ b/src/pages/publish-comment.js
@@ -4,14 +4,14 @@ const ssbMentions = require('ssb-mentions')
 const post = require('./models/post')
 const meta = require('./models/post')
 
-module.exports = async function publishReplyAllPage ({ message, text }) {
+module.exports = async function publishCommentPage ({ message, text }) {
   // TODO: rename `message` to `parent` or `ancestor` or similar
   const mentions = ssbMentions(text).filter((mention) =>
     mention != null
   ) || undefined
   const parent = await meta.get(message)
 
-  return post.replyAll({
+  return post.comment({
     parent,
     message: { text, mentions }
   })
diff --git a/src/pages/reply-all.js b/src/pages/reply-all.js
deleted file mode 100644
index 79fc2e9..0000000
--- a/src/pages/reply-all.js
+++ /dev/null
@@ -1,25 +0,0 @@
-'use strict'
-
-const post = require('./models/post')
-const meta = require('./models/meta')
-const replyAllView = require('./views/reply-all')
-const ssbRef = require('ssb-ref')
-
-module.exports = async function replyPage (parentId) {
-  const parentMessage = await post.get(parentId)
-  const myFeedId = await meta.myFeedId()
-
-  const hasRoot = typeof parentMessage.value.content.root === 'string' && ssbRef.isMsg(parentMessage.value.content.root)
-
-  const rootMessage = hasRoot
-    ? await post.get(parentMessage.value.content.root)
-    : parentMessage
-
-  const messages = hasRoot
-    ? await post.fromRoot(parentMessage.value.content.root)
-    : await post.fromRoot(parentId)
-
-  messages.push(rootMessage)
-
-  return replyAllView({ messages, myFeedId, parentMessage })
-}
diff --git a/src/pages/reply.js b/src/pages/reply.js
index f5f9f13..a7fd4b3 100644
--- a/src/pages/reply.js
+++ b/src/pages/reply.js
@@ -10,9 +10,7 @@ module.exports = async function replyPage (parentId) {
   const myFeedId = await meta.myFeedId()
 
   debug('%O', rootMessage)
-  const messages = await post.fromRoot(rootMessage.key)
-
-  messages.push(rootMessage)
+  const messages = [rootMessage]
 
   return replyView({ messages, myFeedId })
 }
diff --git a/src/pages/views/reply-all.js b/src/pages/views/comment.js
similarity index 67%
rename from src/pages/views/reply-all.js
rename to src/pages/views/comment.js
index 095e04f..c46bcbc 100644
--- a/src/pages/views/reply-all.js
+++ b/src/pages/views/comment.js
@@ -1,12 +1,15 @@
 'use strict'
 
 const {
+  a,
   button,
   form,
-  textarea
+  textarea,
+  p,
+  strong
 } = require('hyperaxe')
 
-const debug = require('debug')('oasis:views:reply-all')
+const debug = require('debug')('oasis:views:comment')
 const template = require('./components/template')
 const post = require('./components/post')
 
@@ -28,11 +31,19 @@ module.exports = async ({ messages, myFeedId, parentMessage }) => {
     })
   )
 
-  const action = `/reply-all/${encodeURIComponent(messages[0].key)}`
+  const action = `/comment/${encodeURIComponent(messages[0].key)}`
   const method = 'post'
 
   return template(
     messageElements,
+    p('Write a ',
+      strong('public comment'),
+      ' on this thread with ',
+      a({ href: 'https://commonmark.org/help/' }, 'Markdown'),
+      '. Messages cannot be edited or deleted. To respond to an individual message, select ',
+      strong('reply'),
+      ' instead.'
+    ),
     form({ action, method },
       textarea({
         autofocus: true,
@@ -41,6 +52,6 @@ module.exports = async ({ messages, myFeedId, parentMessage }) => {
       }, markdownMention),
       button({
         type: 'submit'
-      }, 'reply all'))
+      }, 'comment'))
   )
 }
diff --git a/src/pages/views/components/post.js b/src/pages/views/components/post.js
index 61dc2d2..9db8d7a 100644
--- a/src/pages/views/components/post.js
+++ b/src/pages/views/components/post.js
@@ -34,7 +34,7 @@ module.exports = ({ msg }) => {
     avatar: msg.value.meta.author.avatar.url,
     json: `/json/${encoded.key}`,
     reply: `/reply/${encoded.key}`,
-    replyAll: `/reply-all/${encoded.key}`
+    comment: `/comment/${encoded.key}`
   }
 
   const isPrivate = Boolean(msg.value.meta.private)
@@ -81,8 +81,8 @@ module.exports = ({ msg }) => {
 
   const postOptions = {
     post: null,
-    replyAll: [
-      'replied to ',
+    comment: [
+      'commented on ',
       a({ href: url.parent }, ' thread')
     ],
     reply: [
@@ -151,7 +151,7 @@ module.exports = ({ msg }) => {
         },
         `❤ ${likeCount}`)),
       (isPrivate || isRoot) ? null : a({ href: url.reply }, 'reply'),
-      isPrivate ? null : a({ href: url.replyAll }, 'reply all'),
+      isPrivate ? null : a({ href: url.comment }, 'comment'),
       a({ href: url.json }, 'json')
     ))
 
diff --git a/src/pages/views/reply.js b/src/pages/views/reply.js
index dfc441b..e480d0a 100644
--- a/src/pages/views/reply.js
+++ b/src/pages/views/reply.js
@@ -1,6 +1,9 @@
 'use strict'
 
 const {
+  p,
+  a,
+  strong,
   button,
   form,
   textarea
@@ -11,7 +14,7 @@ const template = require('./components/template')
 const post = require('./components/post')
 
 module.exports = async ({ messages, myFeedId }) => {
-  const likeForm = `/reply/${encodeURIComponent(messages[0].key)}`
+  const replyForm = `/reply/${encodeURIComponent(messages[messages.length - 1].key)}`
 
   let markdownMention
 
@@ -32,7 +35,15 @@ module.exports = async ({ messages, myFeedId }) => {
 
   return template(
     messageElements,
-    form({ action: likeForm, method: 'post' },
+    p('Write a ',
+      strong('public reply'),
+      ' to this message with ',
+      a({ href: 'https://commonmark.org/help/' }, 'Markdown'),
+      '. Messages cannot be edited or deleted. To respond to an entire thread, select ',
+      strong('comment'),
+      ' instead.'
+    ),
+    form({ action: replyForm, method: 'post' },
       textarea({
         autofocus: true,
         required: true,