Optimizely - A/B testing you'll actually use.
StatCounter - StatCounter is a simple but powerful real-time web analytics service that helps you track, analyse and understand your visitors so you can make good decisions to become more successful online.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Histats - Start tracking your visitors in 1 minute!
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
AFSAnalytics - AFSAnalytics.