A slight rant on SMF: coming over from phpBB, I can't tell you how simple SMF is to use and customize. One of my favorite things about it is the ability to link features and settings in a webpage/post, and having fuctional dynamic information fed back to the person clicking the link. Anyways, for your particular problem, all you need to find the section of the template/index you want to make an edit to, and use the ?action=Unread feature.
So for example, if your SMF forum is
http://website.com/forum/index.php ,
http://website.com/forum/index.php?action=Unread would display a page with a list of unread topics, so just make a link to it.
I'm also using the Vertex theme on my forum, with a few personal modifications, including adding a link to Unread posts.
Before I begin, just want to give props to MLM for making an awesome theme, as well as thank him/her for a well documented template. I have literally no training in PHP, much less SMF, so I couldn't of made nearly as many edits as I wanted to without the comments included in his/her theme file.
Now that's out of the way:
If you navigate to the root folder of the Vertex theme, open index.template.php
Scroll down to about line 225, or find this phrase in the file :
// If the user is logged in, display stuff like their name, new messages, etc
and look below that line.
I don't know what the originals are anymore, it was originally all on one line if I recall correctly, and I put mine on different lines so I can see what's going on, and here's what it looks like in mine:
// If the user is logged in, display stuff like their name, new messages, etc. David-Addition: View New Posts
if ($context['user']['is_logged'])
{
echo '
', $txt['vp_help'] ,'
', $context['user']['name'], '
', $txt['bar_symbol'] ,' <a href="', $scripturl ,'?action=pm">', $txt['view_inbox'] ,'</a> ', $txt['bar_symbol'] ,' <a href="', $scripturl, '?action=pm">', $context['user']['messages'], '
', $context['user']['messages'] != 1 ? $txt['msg_alert_messages'] : $txt['message_lowercase'], '</a>', $txt['newmessages4'], '
', $context['user']['unread_messages'], '
', $context['user']['unread_messages'] == 1 ? $txt['newmessages0'] : $txt['newmessages1'] ,'.
', $txt['bar_symbol'] ,' <a href="', $scripturl ,'?action=unread">', $txt['view_unread_category'] ,' since your last visit</a>.
';
}
the next word in the line should be "else{echo...", so if you've pasted past that, you've gone too far.
By the way, the edit is actually really small, this should be the only additional code that wasn't included in the original file:
$txt['bar_symbol'] ,' <a href="', $scripturl ,'?action=unread">', $txt['view_unread_category'] ,' since your last visit</a>.
'
Hoped that helped, and hope you can sort of derive how to make your own edits for other stuff based on this.