Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 20424)
+++ wp-includes/formatting.php	(working copy)
@@ -1468,49 +1468,59 @@
  *
  * @since 0.71
  *
- * @param string $ret Content to convert URIs.
+ * @param string $text Content to convert URIs.
  * @return string Content with converted URIs.
  */
-function make_clickable( $ret ) {
-	// Long strings might contain expensive edge cases ...
-	if ( 10000 < strlen( $ret ) ) {
-		$r = '';
-		// ... break it up
-		foreach ( _split_str_by_whitespace( $ret, 2100 ) as $chunk ) { // 2100: Extra room for scheme and leading and trailing paretheses
-			if ( 2101 < strlen( $chunk ) ) {
-				$r .= $chunk; // Too big, no whitespace: bail.
-			} else {
-				$r .= make_clickable( $chunk );
-			}
+function make_clickable( $text ) {
+	$r = '';
+	$textarr = preg_split( '/(<[^<>]+>)/', $text, -1, PREG_SPLIT_DELIM_CAPTURE ); // split out HTML tags
+	foreach ( $textarr as $piece ) {
+		if ( empty( $piece ) || ( $piece[0] == '<' && ! preg_match('|^<\s*[\w]{1,20}+://|', $piece) ) ) {
+			$r .= $piece;
+			continue;
 		}
-		return $r;
-	}
 
-	$ret = " $ret "; // Pad with whitespace to simplify the regexes
+		// Long strings might contain expensive edge cases ...
+		if ( 10000 < strlen( $piece ) ) {
+			// ... break it up
+			foreach ( _split_str_by_whitespace( $piece, 2100 ) as $chunk ) { // 2100: Extra room for scheme and leading and trailing paretheses
+				if ( 2101 < strlen( $chunk ) ) {
+					$r .= $chunk; // Too big, no whitespace: bail.
+				} else {
+					$r .= make_clickable( $chunk );
+				}
+			}
+		} else {
+			$ret = " $piece "; // Pad with whitespace to simplify the regexes
 
-	$url_clickable = '~
-		([\\s(<.,;:!?])                                        # 1: Leading whitespace, or punctuation
-		(                                                      # 2: URL
-			[\\w]{1,20}+://                                # Scheme and hier-part prefix
-			(?=\S{1,2000}\s)                               # Limit to URLs less than about 2000 characters long
-			[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]*+         # Non-punctuation URL character
-			(?:                                            # Unroll the Loop: Only allow puctuation URL character if followed by a non-punctuation URL character
-				[\'.,;:!?)]                            # Punctuation URL character
-				[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]++ # Non-punctuation URL character
-			)*
-		)
-		(\)?)                                                  # 3: Trailing closing parenthesis (for parethesis balancing post processing)
-	~xS'; // The regex is a non-anchored pattern and does not have a single fixed starting character.
-	      // Tell PCRE to spend more time optimizing since, when used on a page load, it will probably be used several times.
+			$url_clickable = '~
+				([\\s(<.,;:!?])                                        # 1: Leading whitespace, or punctuation
+				(                                                      # 2: URL
+					[\\w]{1,20}+://                                # Scheme and hier-part prefix
+					(?=\S{1,2000}\s)                               # Limit to URLs less than about 2000 characters long
+					[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]*+         # Non-punctuation URL character
+					(?:                                            # Unroll the Loop: Only allow puctuation URL character if followed by a non-punctuation URL character
+						[\'.,;:!?)]                            # Punctuation URL character
+						[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]++ # Non-punctuation URL character
+					)*
+				)
+				(\)?)                                                  # 3: Trailing closing parenthesis (for parethesis balancing post processing)
+			~xS'; // The regex is a non-anchored pattern and does not have a single fixed starting character.
+			      // Tell PCRE to spend more time optimizing since, when used on a page load, it will probably be used several times.
 
-	$ret = preg_replace_callback( $url_clickable, '_make_url_clickable_cb', $ret );
+			$ret = preg_replace_callback( $url_clickable, '_make_url_clickable_cb', $ret );
 
-	$ret = preg_replace_callback('#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]+)#is', '_make_web_ftp_clickable_cb', $ret);
-	$ret = preg_replace_callback('#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret);
+			$ret = preg_replace_callback( '#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]+)#is', '_make_web_ftp_clickable_cb', $ret );
+			$ret = preg_replace_callback( '#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret );
 
+			$ret = substr( $ret, 1, -1 ); // Remove our whitespace padding.
+			$r .= $ret;
+		}
+	}
+
 	// Cleanup of accidental links within links
-	$ret = preg_replace("#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i", "$1$3</a>", $ret);
-	return substr( $ret, 1, -1 ); // Remove our whitespace padding.
+	$r = preg_replace( '#(<a( [^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i', "$1$3</a>", $r );
+	return $r;
 }
 
 /**