Most people only work on the Page-Rank for their main domain. This is not enough in my humble opinion. My blog started off with building more back-links for its domain and managed to achieve a Page-Rank 3 within 9 months. Currently, apart from building back-links for my main domain eg. http://bloggeroftheweb.com, I work on quality back-links for my individual blog posts too eg. SEO & Blogging: 10 Mins Teamwork Success Campaign which has already achieved Page-Rank 2.
Benefits for increasing Page PR:
1. As blogger out there have many software and methods to search for blog posts with Page PR > 0, your page will stand out from the rest when they do a search thus increasing your post visibility. If your blog is dofollow, they would be more than happy to pay a visit and leave a comment too.
2. As you work along with getting more back-links for your blog posts, your blog posts will be exposed to the blogosphere more and if your blog content is unique and rich, it will get popular thus add credibility to your blog.
You should also take a look on how to maintain your blog PageRank SEO & Blogging: Does PageRank Really Matter To You?
