Optimizely - A/B testing you'll actually use.
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
SiteGainer - SiteGainer is an A/B testing and conversion optimization platform.
Evolv - Evolv is the visual editor for web-based projects that are used to find better ways to connect with customers in order to improve marketing economics.
Webtrends Optimize - Webtrends Optimize - a powerful, enterprise-grade Testing and Personalisation platform. AB, MVT & Server-side Testing, Product Recommendations & much more.