The Page Strength SEO Tool (http://www.seomoz.org/page-strength) created by Matthew Inman and Rand Fishkin is a very great tool about which I came to know of recently 
The tool is basically to check your blog/site Search Engine Optimization and provides you with detailed statistics of how you can make your blog rank better 
The tool is very simple to use Just enter your URL
After clicking 'Get Page Strength' you will get your Blog Page Strength just as I got mine for Sizlopedia
Some Relatively Good Features of this tool are:
The Use of Page Strength SEO Tool:
- The Relative Importance and Visibility of a Webpage
- The Potential Strength and Ability of a Page to Rank in the Search Engines
- Data on Popularity, Links & Mentions of the Page Across the Web
The tool is indeed very useful for bloggers and webmasters who want their blog/site to stand out in the building web marketing Industry
The best thing about this tool is that it does not only check your blog popularity on the basis of backlinks rather it uses all the dynamic characterisitics of a blog/site and then ranks it accordingly
Here is a list of sources that this tool checks your blog/site against in order to rank it
- Links pointing to full URL (Source:Yahoo! Site Explorer)
- Links pointing to domain (Source:Yahoo! Site Explorer)
- Title Tag Position at Google (Source: Google)
- Age of Domain (Source: Wayback Machine)
- Links from domains with .edu TLDs (Source:Yahoo)
- Links from domains with .gov TLDs (Source:Yahoo)
- Alexa Rank(Source:Alexa)
- Domain Name Visibility (Source: Google)
- Internal Link Percent (Source:Yahoo! Site Explorer)
- Number of Links to Technorati (Source:Technorati)
- Del.Icio.us Search Results (Source:del.icio.us)
- Listing in DMOZ (Source:Yahoo)
- Links in Wikipedia (Source:Yahoo)
- Google Pagerank of Full Domain (Source: Google)
You can also share your score through Web 2.0 icons provided on the site
So check your Blog Page Strength Now and share it