Piazza is a third-party discussion forum with many features that are designed specifically for use with courses. We encourage you to post questions (and answers!) on Piazza, and read what other questions your classmates have posted.
However, since Piazza is run by another company, we also encourage you to read the privacy policy carefully and only sign up if you are comfortable with it.
If you are not comfortable signing up with your U of T email address, you can access read-only mode. Contact the Course Coordinator (sheila -at- cs -dot- toronto -dot- edu) if you have additional questions about using Piazza.