Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

Simple Poll - The easiest way to create polls in Slack

Babble - A more personalized social network

GitHub Polls - Polls for GitHub issues and readme

LanguageBeast.com - Study English synonyms and antonyms to enrich your vocabulary

minipoll - Create simple shareable polls in seconds