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.
Optimizely - A/B testing you'll actually use.
Clicky - Clicky Web Analytics is a simple way to monitor, analyze, and react to your blog or web site's traffic in real time.
SplitMetrics - SplitMetrics is the A/B testing platform for App Store and Google Play page to discover the most converting icons, screenshots, video, etc.
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.
Intellimize - Convert more. Optimize and personalize for every website visitor.