jQuery is a cross-platform JavaScript library designed to simplify the client-side scripting of HTML. It is free, open-source software using the permissive MIT License. Web analysis indicates that it is the most widely deployed JavaScript library by a large margin.
Gmail is a free, advertising-supported email service offered as part of Google's G Suite, with 15GB of storage, color-coded inbox filters and unsend button.
Kissmetrics is an analytic & metric solution that helps users identify, understand & improve the metrics that drive their online business. Use KISSmetrics to analyze customer behavior across multiple devices and browsers with funnel reports, A/B test reports, revenue reports, and cohort reports.