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.
draw.io - Online diagramming application
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.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Woopra - Track your customers' web and mobile activity, forms, emails, support tickets and more, all in one place with customer analytics. Analyze and take action.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.