Although D2L has a discussions module, piazza.com offers students and instructors features not available in D2L, and the software is now officially UW-Madison-supported. Using piazza.com, students, instructors, and TA’s can post questions or notes (announcements) regarding course assignments, as well as the logistics of the class, and answer other students’ questions. Instructors and TA’s can easily “endorse” some answers or announcements, or add their own answers or comments to existing student answers. For students who are hesitant to pose questions, piazza.com allows questions which may be posted as anonymous to other students (only the instructors or single instructor know who posted the question), or anonymous to everyone – so that no-one (not even the instructor) knows who posted the question (or the answer). Piazza.com allows instructors to avoid answering the same questions over and over again, and additionally offers one place where the answer to someone’s question is also visible to others (if the person asking and answering the questions chose such option).
Overall, piazza.com allows a more productive and nuanced exchange of ideas then email, and definitely a faster exchange than D2L discussions, adding a convenience of choices in addition to the web-interface access at the piazza.com website, participation is also possible through native apps for iOS (iPhone, iPod Touch, iPad), and Android.
For more information, see a complete list of piazza.com features with how-to instructions.