Piazza describes itself as “a place where students can come together to ask, answer, and explore under the guidance of their instructor.” In practice, it’s rather like a fancied-up discussion board. Students can post questions for other students to answer, or post private question for the instructor’s eyes only. In addition, the instructor can post notes (for announcements, or such like) for all students to read. There are a few bells and whistles (for example, the instructor can “validate” a correct response to a student), but largely the purpose seems to be to encourage student interaction for purposes of mutual aid in studying and learning.
Pros: Easy to use interface. It’s good to have a forum in which students can learn/be encouraged to ask their own questions. Anything that gets students to take the lead in learning, rather than just relying on the teacher, is welcome to me.
Cons: If it’s really a big discussion board, why not use an existing service, such as Moodle (at my school), Edmodo, Schoology, even a Facebook group? Does Piazza’s extra functionality really make it worthwhile to add one more site to the students’ on-line agenda?
UPDATE: The good folks at Piazza have contacted me to tell me that Piazza has integration with both Moodle and Facebook connect. I haven’t looked into the details yet, but if so, that would at least address the concern about “one more account to remember.” There is still the question of whether it’s worth using Piazza rather than an alternative service. But given student dislike of Moodle, I imagine they’d prefer Piazza to Moodle, at least.
Schoology, referred to above, is a free LMS (course management system). As an alternative to the better known Moodle, it has the advantage that can be used by just one teacher (doesn't have to be installed/purchased by a school system) and is available entirely online.