My Take
I have used Padlet successfully with students in second through fifth grade, although I can imagine uses at every grade level. It is extremely easy to use and students enjoy the instant results that may be achieved through their efforts. Students see their responses immediately appear on "the wall" and they may also view classmate answers as they are entered.
How I Use It
At my school, Padlet walls have been created for a variety of content topics at each grade level. Second grade students brarinstormed state facts, as well as jobs in the community. Third graders read a Native American book and went to a Padlet wall to write about their wonderings about how these people lived. Fourth graders answered discussion questions related to a class read aloud on a Padlet wall. Even our youngest kindergarteners and first graders used Padlet for practicing sight words. Padlet has offered an interesting new way for students to share with others.
Students do get excited when they see the wall building with responses from their peers, so be prepared for some surprised children.