Michalak, R. (2016). Diigo. Technical Services Quarterly, 33(1), 96–97. doi:10.1080/07317131.2015.1093854
As an experienced Diigo user (before), I found this intro not informative enough to illustrate the core philosophy of Diigo, that is to create another layer on top of web content. This intro focuses too much on the Library, which is important indeed, but does not talk enough about the social engagement piece that (co-)defines Diigo.
Diigo—Digest of Internet Information, Groups and Other stuff—is a secure subscription-based online knowledge management and social bookmarking website. (p. 2)
Users can gather, collect, annotate, and store information discovered on webpages whether they are on PCs, tablets, or mobile devices. (p. 2)
Diigo permit users to annotate PDF documents, create outlines, and share work with team members. (p. 2)
Diigolet is for novice users who principally want to save bookmarks, highlight text, and use sticky-notes. (p. 3)
Diigo Groups is a collaborative, knowledge-sharing research and learning tool that permits subscribers to pool their findings through bookmarks, highlights, and forums. In addition, group members can interact with annotations and sticky notes. (p. 3)