Social Annotation Tool: Diigo

Diigo (http://www.diigo.com/) "Social Annotation" for knowledge users Connect readers of similar interests enable easy interactions!
By combining social bookmarking, clippings, in situ annotation, tagging, full-text search of everything, easy sharing and interactions, Diigo provides a powerful personal tool and a rich social platform.... Don't just bookmark! Highlight important paragraphs and put up digital sticky notes anywhere you wish in the whole wide web. Easily find what is important and why you saved it in the first place! Contribute & share perspectives with your friends or with public. Advanced functionalities / tools to substantially enhance the way you browse, organize, share and search web contents."

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