GitHub Gist - Gist is a simple way to share snippets and pastes with others.
Padlet - Visual boards for organizing anything.
3Cols - Manage your code snippets in the cloud fast, easy and free for personal use forever.
BookWidgets - BookWidgets is an excellent application that let you create engaging exercises in minutes and easily share a varied variety of beautiful and fun activities with your classroom and others.
Simple Snippets - Simple Snippets is place to easily create and manage your code snippets. The main features of the Simple Snippets: code highlighting, snippet groups, public and private snippets.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.