[GameWizard]

Find the template with the existing social bookmarks, and add the following code near the end:

<a href="http://www.yardbarker.com/author/new" onclick="window.open('http://www.yardbarker.com/author/new?pUrl=' + (encodeURIComponent('PERMALINK')).replace(/\./g,'%2E')+'&pHead='+(encodeURIComponent('TITLE')).replace(/\./g,'%2E'), 'yardbarker'); return false;"><img style="border: 0; padding: 0 0 0 15; vertical-align: bottom;" src="http://www.yardbarker.com/images/extern/bark_narrow.gif"></a>

There are 2 variables in there that need to be replaced, PERMALINK and TITLE which should correspond to the thread. Most likely done via simple VBulletin Variables that can be copied from the other social bookmark link codes.