Rank Widgets are actually used to display your rank of blog of various types to be displayed on your blog in form of widget,like traffic rank on alexa,page rank on google,incoming links on yahoo,or technorati rank.And i have seen many blogs using these widgets,to display of there traffic rank or page rank.
Now how to get these widgets as for them you have to visit these respective sites and grab your widget like,
Alexa Traffic rank Widget:-Just go to this site and build any widget you like and get codes and paste in your blog html.
Google Page Rank Widget:-Just read on this post to get this widget.
Technorati Widgets:-Just visit this page and get a lot widgets from here.
Yahoo Links To Page:-Shows of your all incoming links from yahoo.
You will like all these widgets for sure.Now as you will visit these sites you will get limited styles widgets for your blog.SO i have an website for you providing all these widgets at one place and in new designs like below.
So just visit rankwidget.com and click on the widget you want,then will ask for your blog and give you of the codes of all new style widgets.
I loved for sure watching these widgets and gonna use them for sure in my new blog design that soon i will be switching to.