I am a great fan of http://nibbler.silktide.com. It is a great tool that helps you to analyse your website and found areas that you can improve. When you analyse your website it will give it a score between 0 and 10 (10 being the best). One of my websites is currently #1 (http://www.ldstoolbar.com) (Feb 20, 2012)
You can also register and claim websites. To claim a website you will have to either add a custom meta tag in your html <head> or add a custom file. If you use WordPress adding the custom meta tag can be a bit of a pain. Especially if you often change your theme.
So I developed a simple plugin called wpNibbler. This plugin will give you the option to store the verification key in WordPress and it will add it automatically to your html <head>. Now you can change the theme as often as you want. The key will always be added.
wpNibbler is currently at version 1.0. Any updates will be announced here.
Also always happy to get feedback and improvement suggestions.
== Update Feb 20, 2012 ==
Just updated wpNibbler to version 1.0.1. I noticed I used most of the time “Authentication” code when i should have used “Verification” code. Also left some default text in the readme.txt which I removed and I updated the menu from Nibbler to wpNibbler. The functionality hasn’t changed.