Depending on which template you are using the logo Alt tag is normally set as a H1 tag. This is not good for SEO. There should be only 1 H1 tag on any particular page so having on in the header of every page is not good.

PageRank is Google’s stamp of importance which every site receives. PageRank is measured from numbers 1-10: 10 being the most important, and 1 being the least important. What you’re trying to aim for is a decent PageRank for your blog; the higher your PageRank, the more you benefit from it.

In a nutshell, getting several “.gov” and “.edu” backlinks will contribute to your PageRank tremendously, more then just a regular link, or PR6 link for that matter.