diigo well reading research annotation highlighter sticky note archive bookmarke diigo powerful research tool knowledge sharing community download blog sign sign download blog sign sign diigo learning simplified install extension collect save tag online resource easy access anytime annotate annotate web page pdf directly browse online organize organize link reference personal input create structured research base outliner share share research friend classmate colleague associate diigo glance bookmarks easy way collect site want later tag tag collect web page relevant term easy future retrieval personal library complete online knowledge collection place highlights highlight text directly web page personal reference collaboration sticky notes add text comment reminder directly web page sticky note outliner structure research automate streamline diigo personal customization group share research colleague classmate friend collaborative platform knowledge sharing archived web pages store online resource annotation intact forever regardless original source active premium feature million user diigo try free install extension diigo pricing plans term service privacy policy contact