diff --git a/build/index.php b/build/index.php
index c54d361..3e67f81 100644
--- a/build/index.php
+++ b/build/index.php
@@ -131,6 +131,8 @@ $guiConfig = <<<'GUICONFIG'
 			"index.php?action=help"
 		]
 	]},
+	"comment_max_length": {"type": "number", "description": "The maximum allowed length, in characters, for comments", "default": 5000 },
+	"comment_min_length": {"type": "number", "description": "The minimum allowed length, in characters, for comments", "default": 10 },
 	"upload_enabled": {"type": "checkbox", "description": "Whether to allow uploads to the server.", "default": true},
 	"upload_allowed_file_types": {"type": "array", "description": "An array of mime types that are allowed to be uploaded.", "default": [
 		"image/jpeg",
@@ -257,6 +259,7 @@ main:not(.printable) { padding: 2rem 2rem 0.5rem 2rem; background: #faf8fb; box-
 
 blockquote { padding-left: 1em; border-left: 0.2em solid #442772; border-radius: 0.2rem; }
 
+a { cursor: pointer;; }
 a.redlink:link { color: rgb(230, 7, 7); }
 a.redlink:visited { color: rgb(130, 15, 15); /*#8b1a1a*/ }
 
@@ -622,6 +625,8 @@ function makepathsafe($string)
 	$string = preg_replace("/[?%*:|\"><()\\[\\]]/i", "", $string);
 	// Collapse multiple dots into a single dot
 	$string = preg_replace("/\.+/", ".", $string);
+	// Don't allow slashes at the beginning
+	$string = ltrim($string, "\\/");
 	return $string;
 }
 
@@ -937,6 +942,53 @@ function extract_user_from_userpage($userPagename) {
 	return $matches[1];
 }
 
+/**
+ * Sends a plain text email to a user, replacing {username} with the specified username.
+ * @param  string $username The username to send the email to.
+ * @param  string $subject  The subject of the email.
+ * @param  string $body     The body of the email.
+ * @return boolean          Whether the email was sent successfully or not. Currently, this may fail if the user doesn't have a registered email address.
+ */
+function email_user($username, $subject, $body)
+{
+	global $version, $settings;
+	
+	// If the user doesn't have an email address, then we can't email them :P
+	if(empty($settings->users->{$username}->emailAddress))
+		return false;
+	
+	$subject = str_replace("{username}", $username, $subject);
+	$body = str_replace("{username}", $username, $body);
+	
+	$headers = [
+		"content-type" => "text/plain",
+		"x-mailer" => "$settings->sitename Pepperminty-Wiki/$version PHP/" . phpversion(),
+		"reply-to" => "$settings->admindetails_name <$settings->admindetails_email>"
+	];
+	$compiled_headers = "";
+	foreach($headers as $header => $value)
+		$compiled_headers .= "$header: $value\r\n";
+	
+	mail($settings->users->{$username->emailAddress}, $subject, $body, $compiled_headers, "-t");
+	return true;
+}
+/**
+ * Sends a plain text email to a list of users, replacing {username} with each user's name.
+ * @param  string[]	$usernames	A list of usernames to email.
+ * @param  string	$subject	The subject of the email.
+ * @param  string	$body		The body of the email.
+ * @return integer				The number of emails sent successfully.
+ */
+function email_users($usernames, $subject, $body)
+{
+	$emailsSent = 0;
+	foreach($usernames as $username)
+	{
+		$emailsSent += email_user($username, $subject, $body) ? 1 : 0;
+	}
+	return $emailsSent;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -1201,7 +1253,7 @@ class page_renderer
 		<main>
 		{content}
 		</main>
-
+		{extra}
 		<footer>
 			<p>{footer-message}</p>
 			<p>Powered by Pepperminty Wiki v0.14-dev, which was built by <a href='//starbeamrainbowlabs.com/'>Starbeamrainbowlabs</a>. Send bugs to 'bugs at starbeamrainbowlabs dot com' or <a href='//github.com/sbrl/Pepperminty-Wiki' title='Github Issue Tracker'>open an issue</a>.</p>
@@ -1292,6 +1344,7 @@ class page_renderer
 			/// Secondary Parts ///
 
 			"{content}" => $content,
+			"{extra}" => "",
 			"{title}" => $title,
 		];
 
@@ -2001,6 +2054,288 @@ function render_sidebar($pageindex, $root_pagename = "")
 
 
 
+register_module([
+	"name" => "Page Comments",
+	"version" => "0.1",
+	"author" => "Starbeamrainbowlabs",
+	"description" => "Adds threaded comments to the bottom of every page.",
+	"id" => "feature-comments",
+	"code" => function() {
+		global $env;
+		
+		/**
+		 * @api {post} ?action=comment	Comment on a page
+		 * @apiName Comment
+		 * @apiGroup Comment
+		 * @apiPermission User
+		 * @apiDescription	Posts a comment on a page, optionally in reply to another comment. Currently, comments must be made by a logged-in user.
+		 * 
+		 * @apiParam {string}	message	The comment text. Supports the same syntax that the renderer of the main page supports. The default is extended markdown - see the help page of the specific wiki for more information.
+		 * @apiParam {string}	replyto	Optional. If specified the comment will be posted in reply to the comment with the specified id.
+		 * 
+		 *
+		 * @apiError	CommentNotFound	The comment to reply to was not found.
+		 */
+		
+		/*
+		 *   ██████  ██████  ███    ███ ███    ███ ███████ ███    ██ ████████
+		 *  ██      ██    ██ ████  ████ ████  ████ ██      ████   ██    ██
+		 *  ██      ██    ██ ██ ████ ██ ██ ████ ██ █████   ██ ██  ██    ██
+		 *  ██      ██    ██ ██  ██  ██ ██  ██  ██ ██      ██  ██ ██    ██
+		 *   ██████  ██████  ██      ██ ██      ██ ███████ ██   ████    ██
+		 */
+		add_action("comment", function() {
+			global $settings, $env;
+			
+			$reply_to = $_POST["replyto"] ?? null;
+			$message = $_POST["message"] ?? "";
+			
+			if(!$env->is_logged_in) {
+				http_response_code(401);
+				exit(page_renderer::render_main("Error posting comment - $settings->sitename", "<p>Your comment couldn't be posted because you're not logged in. You can login <a href='?action=index'>here</a>. Here's the comment you tried to post:</p>
+				<textarea readonly>$message</textarea>"));
+			}
+			
+			$message_length = strlen($message);
+			if($message_length < $settings->comment_min_length) {
+				http_response_code(422);
+				exit(page_renderer::render_main("Error posting comment - $settings->sitename", "<p>Your comment couldn't be posted because it was too short. $settings->sitename needs at $settings->comment_min_length characters in a comment in order to post it.</p>"));
+			}
+			if($message_length > $settings->comment_max_length) {
+				http_response_code(422);
+				exit(page_renderer::renderer_main("Error posting comment - $settings->sitename", "<p>Your comment couldn't be posted because it was too long. $settings->sitenamae can only post comments that are up to $settings->comment_max_length characters in length, and yours was $message_length characters. Try splitting it up into multiple comments! Here's the comment you tried to post:</p>
+				<textarea readonly>$message</textarea>"));
+			}
+			
+			// Figure out where the comments are stored
+			$comment_filename = get_comment_filename($env->page);
+			if(!file_exists($comment_filename)) {
+				if(file_put_contents($comment_filename, "[]\n") === false) {
+					http_response_code(503);
+					exit(page_renderer::renderer_main("Error posting comment - $settings->sitename", "<p>$settings->sitename ran into a problem whilst creating a file to save your comment to! Please contact <a href='mailto:" . hide_email($settings->admindetails_email) . "'>$settings->admindetails_name</a>, $settings->sitename's administrator and tell them about this problem.</p>"));
+				}
+			}
+			
+			$comment_data = json_decode(file_get_contents($comment_filename));
+			
+			$new_comment = new stdClass();
+			$new_comment->id = generate_comment_id();
+			$new_comment->timestamp = date("c");
+			$new_comment->username = $env->user;
+			$new_comment->logged_in = $env->is_logged_in;
+			$new_comment->message = $message;
+			$new_comment->replies = [];
+			
+			if($reply_to == null)
+				$comment_data[] = $new_comment;
+			else {
+				$parent_comment = find_comment($comment_data, $reply_to);
+				if($parent_comment === false) {
+					http_response_code(422);
+					exit(page_renderer::render_main("Error posting comment - $settings->sitename", "<p>$settings->sitename couldn't post your comment because it couldn't find the parent comment you replied to. It's possible that $settings->adamindetails_name, $settings->sitename's administrator, deleted the comment. Here's the comment you tried to post:</p>
+					<textarea readonly>$message</textarea>"));
+				}
+				
+				$parent_comment->replies[] = $new_comment;
+				
+				$comment_thread = fetch_comment_thread($comment_data, $new_comment->id);
+				
+				$email_subject = "[Notification] $env->user replied to your comment on $env->page - $settings->sitename";
+				
+				foreach($comment_thread as $thread_comment) {
+					// Don't notify the comment poster of their own comment :P
+					if($thread_comment->id = $new_comment->id)
+						continue;
+						
+					$email_body = "Hello, {username}!\n" +
+						"It's $settings->sitename here, letting you know that " . 
+						"someone replied to your comment (or a reply to your comment) on $env->page.\n" . 
+						"\n" . 
+						"They said:\n" . 
+						"\n" . 
+						"$new_comment->message" . 
+						"\n" . 
+						"You said on " . date("c", strtotime($thread_comment->timestamp)) . ":\n" . 
+						"\n" . 
+						"$thread_comment->message\n" . 
+						"\n";
+					
+					email_user($thread_comment->username, $email_subject, $email_body);
+				}
+			}
+			
+			// Save the comments back to disk
+			if(file_put_contents($comment_filename, json_encode($comment_data, JSON_PRETTY_PRINT)) === false) {
+				http_response_code(503);
+				exit(page_renderer::renderer_main("Error posting comment - $settings->sitename", "<p>$settings->sitename ran into a problem whilst saving your comment to disk! Please contact <a href='mailto:" . hide_email($settings->admindetails_email) . "'>$settings->admindetails_name</a>, $settings->sitename's administrator and tell them about this problem.</p>"));
+			}
+			
+			http_response_code(307);
+			header("location: ?action=view&page=" . rawurlencode($env->page) . "&commentsuccess=yes#comment-$new_comment->id");
+			exit(page_renderer::render_main("Comment posted successfully - $settings->sitename", "<p>Your comment on $env->page was posted successfully. If your browser doesn't redirect you automagically, please <a href='?action=view&page=" . rawurlencode($env->page) . "commentsuccess=yes#comment-$new_comment->id'>click here</a> to go to the comment you posted on the page you were viewing.</p>"));
+		});
+		
+		if($env->action == "view") {
+			page_renderer::register_part_preprocessor(function(&$parts) {
+				global $env;
+				$comments_filename = get_comment_filename($env->page);
+				$comments_data = file_exists($comments_filename) ? json_decode(file_get_contents($comment_filename)) : [];
+				
+				
+				$comments_html = "<aside class='comments'>" . 
+					"<h2>Comments</h2>\n" . 
+					"<h3>Post a Comment</h3>\n";
+				
+				if($env->is_logged_in) {
+					$comments_html .= "<form class='comment-reply-form' method='post' action='?action=comment&page=" . rawurlencode($env->page) . "'>\n" . 
+						"\t<textarea name='message' placeholder='Type your comment here. You can use the same syntax you use when writing pages.'></textarea>\n" . 
+						"\t<input type='hidden' name='reply-to' />\n" . 
+						"\t<input type='submit' value='Post Comment' />\n" . 
+						"</form>\n";
+				}
+				else {
+					$comments_html .= "<form class='comment-reply-form disabled no-login'>\n" . 
+					"\t<textarea disabled name='message' placeholder='Type your comment here. You can use the same syntax you use when writing pages.'></textarea>\n" . 
+					"\t<p><a href='?action=login&returnto=" . rawurlencode("?action=view&page=" . rawurlencode($env->page)) . "'>Login</a> to post a comment.</p>\n" . 
+					"\t<input disabled type='submit' value='Post Comment' />\n" . 
+					"</form>\n";
+				}
+				$comments_html .= render_comments($comments_data);
+				
+				$comments_html .= "</aside>\n";
+				
+				$parts["{extra}"] = $comments_html . $parts["{extra}"];
+			});
+		}
+	}
+]);
+
+/**
+ * Given a page name, returns the absolute file path in which that page's
+ * comments are stored.
+ * @param  string $pagename The name pf the page to fetch the comments filename for.
+ * @return string           The path to the file that the 
+ */
+function get_comment_filename($pagename)
+{
+	global $env;
+	$pagename = makepathsafe($pagename);
+	return "$env->storage_prefix$pagename.comments.json";
+}
+
+/**
+ * Generates a new random comment id.
+ * @return string A new random comment id.
+ */
+function generate_comment_id()
+{
+	$result = base64_encode(random_bytes(16));
+	$result = str_replace(["+", "/"], ["-", "_"], $result);
+	return $result;
+}
+
+/**
+ * Finds the comment with specified id by way of an almost-breadth-first search.
+ * @param  array $comment_data	The comment data to search.
+ * @param  string $comment_id	The id of the comment to  find.
+ * @return object				The comment data with the specified id, or
+ *                       		false if it wasn't found.
+ */
+function find_comment($comment_data, $comment_id)
+{
+	$subtrees = [];
+	foreach($comment_data as $comment)
+	{
+		if($comment->id === $comment_id)
+			return $comment;
+		
+		if(count($comment->replies) > 0) {
+			$subtrees = $comment->replies;
+		}
+	}
+	
+	foreach($subtrees as $subtree)
+	{
+		$subtree_result = find_comment($subtree);
+		if($subtree_result !== false)
+			return $subtree;
+	}
+	
+	return false;
+}
+
+/**
+ * Fetches all the parent comments of the specified comment id, including the
+ * comment itself at the end.
+ * Useful for figuring out who needs notifying when a new comment is posted.
+ * @param	array		$comment_data	The comment data to search.
+ * @param	string		$comment_id		The comment id to fetch the thread for.
+ * @return	object[]	A list of the comments in the thread, with the deepest
+ * 						one at the end.
+ */
+function fetch_comment_thread($comment_data, $comment_id)
+{
+	foreach($comment_data as $comment)
+	{
+		// If we're the comment they're looking for, then return ourselves as
+		// the beginning of a thread
+		if($comment->id === $comment_id)
+			return [ $comment ];
+		
+		if(count($comment->replies) > 0) {
+			$subtree_result = fetch_comment_thread($comment->replies, $comment_id);
+			if($subtree_result !== false) {
+				// Prepend ourselves to the result
+				array_unshift($subtree_result, $comment);
+				return $subtree_result; // Return the comment thread
+			}
+		}
+	}
+	
+	return false;
+}
+
+/**
+ * Renders a given comments tree to html.
+ * @param	object[]	$comments_data	The comments tree to render.
+ * @param	integer		$depth			For internal use only. Specifies the depth
+ * 										at which the comments are being rendered.
+ * @return	string		The given comments tree as html.
+ */
+function render_comments($comments_data, $depth = 0)
+{
+	if(count($comments_data) == 0) {
+		if($depth == 0)
+			return "<p><em>No comments here! Start the conversation above.</em></p>";
+		else
+			return "";
+	}
+	
+	$result = "<div class='comments-list" . ($depth > 0 ? " nested" : "") . "' data-depth='$depth'>";
+	
+	foreach($comments_data as $comment) {
+		$result .= "\t<div class='comment' id='comment-$comment->id'>\n";
+		$result .= "\t<p class='comment-header'>$comment->username said:</p>";
+		$result .= "\t<div class='comment-body'>\n";
+		$result .= "\t\t" . parse_page_source($comment->message);
+		$result .= "\t</div>\n";
+		$result .= "\t<div class='reply-box-container'></div>\n";
+		$result .= "\t<p class='comment-footer'>";
+		$result .= "\t\t<button class='reply-button'>Reply</button>\n";
+		$result .= "\t\t<a class='permalink-button' href='#comment-$comment->id'>&#x1f517;</a>\n";
+		$result .= "\t\t&#x1f557; <time datetime='" . date("c", $comment->timestamp) . "'>" . date("l jS \of F Y \a\\t h:ia T", $comment->timestamp) . "</time>\n";
+		$result .= "\t</p>\n";
+		$result .= "\t" . render_comments($comment->replies) . "\n";
+		$ersult .= "\t</div>";
+	}
+	$result .= "</div>";
+	
+	return $result;
+}
+
+
+
+
 register_module([
 	"name" => "Settings GUI",
 	"version" => "0.1.1",
diff --git a/module_index.json b/module_index.json
index 0717bfe..4ccafe6 100755
--- a/module_index.json
+++ b/module_index.json
@@ -44,6 +44,15 @@
         "lastupdate": 1450704211,
         "optional": false
     },
+    {
+        "name": "Page Comments",
+        "version": "0.1",
+        "author": "Starbeamrainbowlabs",
+        "description": "Adds threaded comments to the bottom of every page.",
+        "id": "feature-comments",
+        "lastupdate": 1494686069,
+        "optional": false
+    },
     {
         "name": "Settings GUI",
         "version": "0.1.1",
@@ -104,7 +113,7 @@
         "author": "Starbeamrainbowlabs",
         "description": "Adds a user preferences page, letting pople do things like change their email address and password.",
         "id": "feature-user-preferences",
-        "lastupdate": 1490040319,
+        "lastupdate": 1492444821,
         "optional": false
     },
     {
diff --git a/peppermint.guiconfig.json b/peppermint.guiconfig.json
index 04ed7bb..66ef6ad 100644
--- a/peppermint.guiconfig.json
+++ b/peppermint.guiconfig.json
@@ -109,6 +109,8 @@
 			"index.php?action=help"
 		]
 	]},
+	"comment_max_length": {"type": "number", "description": "The maximum allowed length, in characters, for comments", "default": 5000 },
+	"comment_min_length": {"type": "number", "description": "The minimum allowed length, in characters, for comments", "default": 10 },
 	"upload_enabled": {"type": "checkbox", "description": "Whether to allow uploads to the server.", "default": true},
 	"upload_allowed_file_types": {"type": "array", "description": "An array of mime types that are allowed to be uploaded.", "default": [
 		"image/jpeg",
diff --git a/theme_default.css b/theme_default.css
index ea7e4a0..b9c5720 100644
--- a/theme_default.css
+++ b/theme_default.css
@@ -51,6 +51,7 @@ main:not(.printable) { padding: 2rem 2rem 0.5rem 2rem; background: #faf8fb; box-
 
 blockquote { padding-left: 1em; border-left: 0.2em solid #442772; border-radius: 0.2rem; }
 
+a { cursor: pointer;; }
 a.redlink:link { color: rgb(230, 7, 7); }
 a.redlink:visited { color: rgb(130, 15, 15); /*#8b1a1a*/ }