Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

Outgrow - Enabling marketers boost conversion with interactive, beautiful & viral quizzes/calculators.

Chargify - Chargify is the best online billing software for all of your Recurring Billing needs. Learn more about simplifying your Subscription Billing today.

Quizzes for Pages - Quizzes for Pages is an application to create and share quizzes on your Facebook Page.

Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.

Poll Everywhere - Audience response system that uses mobile phones, twitter, and the web. Responses are displayed in real-time on gorgeous charts in PowerPoint, Keynote, or web browser.