https://twitter.com/
Twitter is a Web 2.0 tool that enables users to share short messages in real-time and read other real-time messages from other Twitter users.
Twitter is a great question forum for teachers from students. For example, you could set up an account labelled, "Social Sciences 10" and students can tweet questions to the account. The teacher can answer the questions via Twitter, or address them in class.
Depending on your school's policies on procedure, Twitter is also a great tool for in class as well. During a work period, students can tweet questions to the teacher instead of getting up. This allows students to maintain anonymity and eliminates the distraction of students getting up to ask questions.
Twitter is also a great way to convey interesting information to students. Maybe on your Social Sciences 9 account, you tweet news that is relevant to the course. This may peak students' interest in the content.
Twitter is a great resource for education because it allows students to connect with their teachers and peers in a casual environment. Many students may feel uncomfortable in the classroom setting, which prevents them from asking questions. Twitter can be anonymous, and allows students to ask questions from the comfort of their own homes.
There is no minimum age for Twitter users.
