I'm trying to use Watir on a page that has a large number of ads and it's really slowing down my tests. Why when Watir launches Firefox do my extensions (Adblock, etc.) not carry over and is it possible to install them?
Yes, you can do it. Let' assume you to want use Firebug extension..
First download the Firebug xpi file, then use the following code:
profile = Selenium::WebDriver::Firefox::Profile.new profile.add_extension "../path/to/firebug.xpi" b = Watir::Browser.new :firefox, :profile => profile