Optimizely - A/B testing you'll actually use.
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.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Clicky - Clicky Web Analytics is a simple way to monitor, analyze, and react to your blog or web site's traffic in real time.
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.
KISSmetrics - Giving you the knowledge you need to make better decisions. Kissmetrics is a revolutionary person-based analytics platform for your whole team. Get product, sales, marketing, customer support working together to improve the metrics that matter.