Test Everything is an interesting page that allows you to run about 150 different types of tests on the URLs of your choice. One of the functions offered is a tool that allows you to obtain the specific IP address of any web page and another allows you to visualize the contents of the cache of google.
There really is an impressive array of tools available for free at this site and they are organized into the following categories: CSS and HTML validators, SEO tools, Social services, web proxies network tools, text tools, image tools and miscellaneous tools. Basically just enter a URL into the provided box, pick the tool you want to use, and get instant results.
Tester.jonasjohn.de In Their Own Words
“This is a personal and uncommercial project managed by Jonas John. Since May 2007 I collected 128 entries to many different webservices. Resources and libraries used: Yahoo! UI Library (YUI), Highslide JS, Silk Icons by Mark James.”
Why Tester.jonasjohn.de It Might Be A Killer
There really are a lot of options on this site that can provide you with a wealth of information in an easy way. This could become a popular site amongst webmasters and internet researchers.
Some Questions About Tester.jonasjohn.de
Given that many of the tools available will not be understood by the layman, have they considered including an FAQ section that explains how people can use all of these great tools? 
