Here is a very useful Mozilla Firefox addon that can provide detailed information regarding a website.
Download and install Flagfox from here.
Once installed, go to Tools > Addons and select Options to customize Flagfox (regarding where it should be displayed as well as assigning shortcuts for various actions).
What makes this addon very useful is that not only it provides the basic info regarding where a specific website’s server is hosted but also various other stats like ISP, whois and DNS info too. Apart from this one can do IP lookups, rank lookups, run ping / trace and other connectivity status tools and much more.
This addon can also be used to generate a website profile based on where it is located as well as for various SEO related stuff (for webmasters).
Overall a super useful addon that is very light on resources and provides lots of useful info.