Easily the most complete A/B testing and conversion rate optimization software for WordPress.
Includes Conductrics Web Actions scripts in your pages, which makes it easy to test changes to your pages and track their success.
Fittest plugin for WordPress lets you experiment with different variations of content on your site.
This plugin help you and Google Analytics to create experiments that test which version of a landing page leads better.
Adaptive A/B testing with Conductrics -- Auto-Optimize Conversions on your WordPress Site.