Well Mozrank tells about popularity or importance of link. It represent importance of link among search engines. Sites earn Mozrank by Quality of content and other pages link to it. Mozrank is present on scale of 1 to 10 , the highter the the score better it is mean its popular in search engines. Good thing about Mozrank is that its updated periodically so if Mozrank is going up then its good for site and if you see down fall in Mozrank than you may need to work on your site and can add quality content , normally Mozrank falls due to lack of updated quality content on site.
Useotools Mozrank Checker is online free one click tool that can find Mozrank, Page Authority Score (PA)and Domain Authority Score (DA). Usage of this tool is very simple you just input your link and press submit button and next you will be it result page.