Envelopes-click private messaging or quick links on the blue line near top of the page and then on the left menu click either your subscriptions or bookmarks link and underneath your list it tells you what the different envelopes mean x
[h=5]Icon Legend[/h]<dl><dt>
</dt><dd>Contains unread posts</dd><dt>
</dt><dd>Contains no unread posts</dd><dt>
</dt><dd>Hot thread with unread posts</dd><dt>
</dt><dd>Hot thread with no unread posts
</dd></dl>