aghop.ORG allows you to relate categories on the web so others to hop your personal web and for you to discover related categories that other people find useful!
"(...) has the most power and value in vertical search-style app.s, where a community of experts contributes to a pool of content that is then rated by other experts, assuring that the best available content is recognized and becomes readily available."
"network is decentralized, with each node—be it a tag, individual, or object—able to connect to another within the system. What arises, when enacted on a large enough scale, is rhizomatic: multiple points of entry for multiple participants"
Diigo is about "Social Annotation", a superset of social bookmarking. We believe that the social annotation service provided by Diigo can really enhance your experience for online browsing and interactions, and for information gathering and sharing.
F. Mitzlaff, M. Atzmueller, D. Benz, A. Hotho, and G. Stumme. Analysis of Social Media and Ubiquitous Data, volume 6904 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2011)
F. Mitzlaff, D. Benz, G. Stumme, and A. Hotho. HT '10: Proceedings of the 21st ACM Conference on Hypertext and Hypermedia, page 265--270. New York, NY, USA, ACM, (2010)
H. Halpin, V. Robu, and H. Shepherd. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 211--220. New York, NY, USA, ACM, (2007)