Google Site Verification
From HAA Best Practices Wiki
The Google site Verification plugin inserts a meta tag in the header of your home page. This tag allows Google to verify that the site belongs to you, for the purpose of using Google's Webmasters Tools. You access the plugin by going to Joomla->Extensions->Plugin Manager-System - Google Verification.
Insert your Google key (see prior page) in the 'content' field and save the page. Now you can ask Google to verify your site.