Have you noticed that SMF page description in google isn't very effective? Try doing a site:perkiset.org and all the pages comes up like this:
SMF post subject here
Welcome, Guest. Please login or register. September 01, 2007, 09:30:01 AM. 1 Hour, 1 Day, 1 Week, 1 Month, Forever. Login with username, password and ...
The default description is
<meta name="description" content="', $context['page_title'], '" />
which is exactly the same as the page title and google is totally ignoring it.
I checked the SMF site and didn't see any mod for it. That's kind of odd with all the smf forums out there...
Anyway, if any of you guys ever come up with a way to create a better description, please post it here

I'll keep looking and do the same...