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.
UseResponse - Open-source, self-hosted customer feedback software, live chat and helpdesk system that you can install on your server. Organize documentation using knowledge base and get feedback from social networks with centralized system
Adobe Analytics - Adobe Analytics is an industry-leading solution that empowers you to understand your customers as people and steer your business with customer intelligence.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Mixpanel - Mixpanel is the most advanced analytics platform in the world for mobile & web.
Olark - Real-time chat and monitoring of your website visitors through Google Talk and Jabber.