"Diigo stands for "Digest of Internet Information, Groups and Other stuff." It is a social bookmarking program that allows you to save your 'favourites' online, so that they can be accessible from any computer with an internet connection. However, Diigo does much more than this."
"Diigo allows its users the options to bookmark, highlight, and tag selected web-pages that can be retrieved from any computer, any time, any place. Users find its features of highlighting and tagging a great way to organize online research. "
"Instead of just bookmarking, Diigo allows you to highlight text and attach sticky notes to specific parts of web pages. Diigo highlights and sticky notes are persistent in the sense that whenever you return to the original web page,"
"In a nutshell, Diigo Education Domain supports Google single sign-on but it also recognizes users based on approved school email domain. So approval of your school domain will enable your school domain users to easily sign in / create special Diigo education accounts (with special edu features) instead of just regular Diigo account. "