Like many of us, we had problems with this extension along with being able to view / post to in their documentation. After digging around I found where many folks will run into errors.
According to the developer you should add in some code to
frontend / your store / default / template / catalog / view.phtml
This MIGHT work if you don’t have the EasyTabs extension installed.
IF you DO, then what you actually need to do is open up:
frontend / your store / default / template / easytabs / catalogproductview.phtml
and then add in this code:
<!-- social bookmark -->
<?php echo $this->getChildHtml('bookmarks') ?>
The code that was on the developer’s site was BORKED. Malformed and probably wouldn’t work.
After I did this I refreshed my site and blammo! Social bookmarks :D
Good luck and hope this helps!