--- /Users/ben/Desktop/feedparser.orig.py
+++ feedparser.py
@@ -441,8 +441,7 @@
                 lastvalue.append(line)
                 continue
             if lastheader:
-                # XXX reconsider the joining of folded lines
-                lhdr = EMPTYSTRING.join(lastvalue)[:-1].rstrip('\r\n')
+                lhdr = self._fold(lastheader, lastvalue)
                 self._cur[lastheader] = lhdr
                 lastheader, lastvalue = '', []
             # Check for envelope header, i.e. unix-from
@@ -476,5 +475,10 @@
             lastvalue = [line[i+1:].lstrip()]
         # Done with all the lines, so handle the last header.
         if lastheader:
-            # XXX reconsider the joining of folded lines
-            self._cur[lastheader] = EMPTYSTRING.join(lastvalue).rstrip('\r\n')
+            self._cur[lastheader] = self._fold(lastheader, lastvalue)
+
+    def _fold(self, header, lines):
+        if header.lower() in ['subject', 'comments', 'keywords']:
+            return EMPTYSTRING.join([l.rstrip('\r\n') for l in lines])
+        else:
+            return EMPTYSTRING.join(lines)[:-1].rstrip('\r\n')