A list of social bookmarking websites. Social bookmarking websites are websites where users can save links to webpages (usually with other information such as keywords), and then get recommendations based on the webpages they already like (and/or the other users they are connected to socially).
StumbleUpon is a social bookmarking website where its users add links to webpages they like (along with comment descriptions and keyword tags). Users can also follow one another. Recommended webpages are provided to users based on their interests, pages they like, and who they follow. Users can also 'stumble' for pages. This involves randomly selected pages being displayed within StumbleUpon (underneath a StumbleUpon bar). Users can give a thumbs up to the stumbled pages they like (or a thumbs down to the pages they don't like). This affects the likelihoods of other pages being stumbled.
Delicious is a social bookmarking site where users can save links (along with link titles, keywords and comment descriptions), and get a list of recommendations for other links, based on the links they have saved and the other users they follow.
Reddit is a set of forums (known as reddits and subreddits) with social bookmarking characteristics. Users can start two different types of threads: text and link (i.e. a single webpage URL). The threads can be voted up or down, and can be sorted in a variety of ways. A link cannot be posted more than once to the same reddit/subreddit.
Diigo, a social bookmarking website with tools for text highlighting and webpage caching.
A social bookmarking site (and social bookmarking browser add-on) where users can also save and review the webpages they bookmark.
A social bookmarking website for webpages, news, and videos. Posted links can be up-voted (which helps boost the link poster's 'reputation rank').
Pearltrees describes itself as a social library. It is a website where users can build 'pearl trees' i.e. an online diagram made up of branching spheres called 'pearls'. The pearls can be webpage links, files, photos, notes, and new pearltrees. Pearltrees has an optional browser extension called a 'pearler' which allows its users to create webpage pearls while they browse. While on a pearl, clicking on the 'related' button searches and displays a set of related pearls created by other users.
BibSonomy describes itself as a system for sharing bookmarks and lists of literature. Searching for a particular updates/keyword brings up two columns of search results: bookmarks (webpage links) and publications (academic articles).
GiveALink describes itself as a social annotation, organisation, recommendation, and navigation system for the web. The site has a bookmark visualisation tool and has online link related games.
An academic social bookmarking website, for saving and sharing scholarly articles.