Optimizely - A/B testing you'll actually use.
invesp Pii Testing Engine - invesp Pii testing engine offers A/B testing solution for site optimization.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
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.
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.
Chartbeat - Chartbeat shows you real-time traffic to your website and allows you to set alerts for any downtime or spikes in traffic.