Social Bookmarking

The website del.icio.us (pronounced as "delicious") is a social bookmarking web service for storing, sharing, and discovering web bookmarks. The site was founded by Joshua Schachter in late 2003, and is now part of Yahoo!.

StumbleUpon is a web browser plugin that allows its users to discover and rate webpages, photos, videos, and news articles. These webpages are typically presented when the user -- known within the community as a Stumbler -- clicks the "Stumble!" button on the browser's toolbar. StumbleUpon chooses which new webpage to display based on the user's ratings of previous pages, ratings by his/her friends, and by the ratings of users with similar interests. i.e. it is a recommendation system which uses peer and social networking principles. There is also one-click blogging built in as well. Users can rate, or choose not to rate, any webpage with a thumbs up or thumbs down, and clicking the Stumble button resembles "channel-surfing" the web. Toolbar versions exist for Firefox, Mozilla Application Suite and Internet Explorer.

SWiK is a wiki website allowing people to share information about open source projects.

Social Bookmark Script generator

Simple recognizable widgets to help your visitors save and promote your website or blog to the social bookmarking and feed reader services!

Digg is a community-based popularity website with an emphasis on technology and science articles, recently expanding to a broader range of categories such as politics and entertainment. It combines social bookmarking, blogging, and syndication with a form of non-hierarchical, democratic editorial control.

reddit is a social news website where users can post links to content on the web. Other users may then vote the posted links up or down, causing them to appear more or less prominently on the reddit home page.

Slashdot

Simpy is a web-based personal and social bookmarking service. The service launched in May 2004 and is one of the oldest social bookmarking services that still operates independently (del.icio.us was acquired by Yahoo! and Furl was acquired by Looksmart). Simpy uses tags and tag clouds to aid bookmark recall and allows bookmarks to be shared or kept private. It has a well-documented REST API suitable for mashups and integration with other applications and services. Simpy's founder is one of the developers of Lucene, a popular text search toolkit, so Simpy has powerful search capabilities. The service allows for cooperation, via groups with different levels of privacy, and for discovery of relevant and new links via its watchlists and watchlist filters. In addition to saving, tagging, and sharing links, users can also save, tag, and search free-text notes. Most data pages also have RSS feeds.

It's the easiest way to save and share important things you see on the Web.