Gaggle is a group of online communication tools for teachers and students that filters content and monitors use. It provides features like email accounts for students, online storage of files and documents, and a way for teachers to assign and students to submit work. Content on Gaggle, including images and text, is monitored. Teachers can approve YouTube videos for students to access on GaggleTube. Students can chat with teachers and add approved friends on the social wall feature. The document provides instructions on logging into Gaggle and describes the various tools available on the site.