In our large undergraduate systems class, Piazza greatly smoothed the process of helping students with programming assignments, especially with our increasing enrollments in the computer science department. In my graduate course on computer networks, Piazza noticeably increased the level of student participation in discussion of papers online before lecture, which also improved the in-class discussion.
Piazza has been absolutely incredible for our course this semester. It's been great to be able to easily communicate with the entire class at once without creating annoying email lists or relying on them to visit the course webpage.
Piazza is the best discussion forum I've ever used in my 400-strong enrollment class (CS125). It encourages students to work together and to discuss concepts and misconceptions together in a timely, coherent and easily searchable format. If you're not using Piazza to help your students learn and deeply connect with the course content - then your students are missing out and the ability for yourself, TAs and others to support individual students and the class as a whole will be diminished.
Instructors can create a Piazza for their class with a single click.
Students and instructors are automatically enrolled with appropriate roles, based on the course roster.
When clicking on Piazza in Illinois Compass, users are automatically signed in to Piazza, so there's no need to remember a separate user name and password.