Optimizely - A/B testing you'll actually use.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
SplitMetrics - SplitMetrics is the A/B testing platform for App Store and Google Play page to discover the most converting icons, screenshots, video, etc.
Google Analytics - Improve your website to increase conversions, improve the user experience, and make more money using Google Analytics. Measure, understand and quantify engagement on your site with customized and in-depth reports.
Webtrends Optimize - Webtrends Optimize - a powerful, enterprise-grade Testing and Personalisation platform. AB, MVT & Server-side Testing, Product Recommendations & much more.
Crazy Egg - Through Crazy Egg's heat map and scroll map reports you can get an understanding of how your visitors engage with your website so you can boost your conversion rates.