Diigo is a cloud-based tool that allows users to collect, organize, and share information from the internet. It can be used by teachers and students to collaboratively conduct research online. Key features include bookmarking web pages, highlighting text, and adding annotations. Teachers can create student accounts and groups to facilitate collaboration and sharing of research findings. Using Diigo transforms the research process from individual piles of paper printouts to an organized online format where students can interact with each other's work.