Diigo

Diigo is a social bookmarking, research and knowledge sharing tool. It lets you make personal notes and highlight text on web pages and share them with others.

Cost: Free.and premium versions
Available: Hosted
Website: https://www.diigo.com/
Categories: curationresearch

Ranking on Top 100 Tools for Learning 2015: 42  See more at http://c4lpt.co.uk/top100tools/diigo/