Reading from another forum on this community, many bloggers disclosed their PageRank to be within the 0-2 range. Even for a blog I have that has not been updated often, the PageRank is 2. What is your blog's PageRank? Is it a business or personal blog?

I think the relevance of a Blogs page rank is dependent on the purpose of the blog. I am setting up two blogs in WordPress for a client who is going to use them as marketing tools/micro-sites for their business. In this case the majority of the traffic is going to come from referrals or from links to the main corporate website or the Linkedin profiles of the two partners. In this case, PageRank is not important. I have a friend who has set up a blog to hi-light his writing and two secure blogging jobs with online publications. In his case, the PageRank would probably carry more weight.

I just wanna focus on my SERP any way if you don't have any page rank on your site you are useless SEO.

Not necessarily. Page Rank does take into consideration the age of the site and if the site was recently created, it may not be crawled yet or have accumulated time authority.

use blog networks for serp and building links

like blogcatalog and mybloglog

You can find many blogs that have PR6 and higher and when you take a look at their web rankings and link popularity, you will find them at the top and being linked to by many other blogs and reliable sources.