Regarding SEO Book toolbar
 

Of late I have made the installation of SEOBook and Seaquake toolbars on the computer of mine. All these are identical looking. I cannot find out where the difference lies. Can somebody tell me? What are exactly their best functions? Do I need each one of them or one is enough? While I was setting these up, I was questioned if I required Delicious or technorati plugins � is there utility limited to pages only or something more are there? Just what indication do numbers on SEMrush costs and rank give?