well u cant really sit there checking over 100k sites with a firefox extension.... i wanted to know if u could mass check em
http://tools.seobook.com/firefox/seo-for-firefox.html This is a really good tool...It covers everything you need including the no follow and will automatically highlight all the no follows for you... This is the one I use.
If you want to check do follow blogs there is an application available in the download section to check that. What type of sites you want to mass check?