I actually forgot all about my blog because I haven't posted in it for quite some time. The only kind of advertising I've done with that blog is through social bookmarking sites and my PR is 2 which is awesome for me!
Most social bookmarking sites use nofollow, which prevent a backlink from passing seo\pagerank weight. You most likely have other backlinks, view your external backlinks for Google at Google Webmasters Central. http://www.google.com/webmasters