Diigo is a research and collaboration tool that allows users to bookmark web pages, highlight content, and add notes. It has features for personal and collaborative research. Users can organize bookmarks and annotations by tags or lists and access them from any device. Diigo also allows for sharing bookmarks and annotations. Educators can apply for status to access additional educational features like creating student accounts and class groups for collaborative work. As an educator, you get access to the teacher console and can manage student accounts and groups.