Popplet is a good way to brainstorm with the students. It allows for a collaborative mind-mapping experience. Also it is a great tool for note-taking and organizing.
Creativity enlarges the possibilities and varities of using popplets in the classroom. Here is a good example of using popplets.
In projects, you can use it with great efficiency. For example we used popplets in our etwinning project with another great app, padlet. Students shared their interests in a popplet page, then we gave links to padlets. Just click on the popplet page to search more about it.