edutagger is a social bookmarking service for K-12 learners and educators, allowing you to store your web links online and share them with others, all within an educational context.
eHub is a constantly updated resource of web applications, services or sites with a focus on next generation web (web 2.0), social software, blogging, Ajax, Ruby on Rails, location mapping, open source, folksonomy, design and digital media sharing.
"If I get my friends to use Flickr, it gets better for me and for them. (...) Latest things matter. There are lots of interesting slices that can be taken. Slice by user, time, tags, location, relationship to other tags, "interestingness"."
R. Abbasi, S. Chernov, W. Nejdl, R. Paiu, und S. Staab. Advances in Information Retrieval, Volume 5478 von Lecture Notes in Computer Science, Seite 654--661. Springer Berlin / Heidelberg, (2009)