I like the different modes of posting questions. Tagging only a certain group of people is a nice feature. That is, if a student has doubt only for instructors and not the whole class, he/she can easily apply that specific feature.

I like that Piazza allows students to post notes or questions to their peers in a course in a way that is intuitive and fairly easy to use. It is very useful that on the landing page one can see what the latest posts have been and how many are unanswered under the 'class at a glance' section. I also like that at the top of the page, assuming Piazza is being used for a class where there are different assignments, one can see a list of tabs with each assignment that they can then click to go to. Overall, the interface is fairly simple but effective and allows for students (or users in general) to access information easily and quickly.

Announcement, sharing of materials, and posting of grades, Q&As become easy with Piazza!