Diigo (DEE-go) is a Social bookmarking website which allows signed users to bookmark and tag web-pages. More exclusively, it allows users to highlight any part of a webpage and attach sticky notes to specific highlights or to a whole page. These annotations can be kept private, shared with a group within Diigo or a special link forwarded to someone else. The name “Diigo” is an abbreviation for “Digest of Internet Information, Groups and Other stuff”.
The launch of Diigo met with mixed responses from the unimpressed to the enthusiastic. …

Furl (from File Uniform Resource Locators) is a free social bookmarking website that allows members to store searchable copies of webpages and share them with others. Every member receives 5 gigabytes of storage space. The site was founded by Mike Giles in 2003 and purchased by LookSmart in 2004.
Features
Furl enables members to bookmark, annotate, and share web pages. Topics are used to categorize saved sites, similar to the tagging feature of other social websites. Additionally, a user may write comments, save clippings, assign each bookmark a rating and keywords …

Ma.gnolia is a social bookmarking web site comparable to Delicious or Simpy. A prominent feature that distinguishes it from other similar web sites is the group feature, which allows several users to share a common collection of bookmarks. The group is managed by a selected number of group managers. Users may rate bookmarks and mark bookmarks as private.

Google Bookmarks is a free online bookmark storage service, available to Google Account holders.
The service allows one to bookmark favorite websites and add labels or tags, and also notes.
Labels and notes are searchable, and users can access their bookmarks from any computer by signing in on one’s Personalized Homepage.
Google toolbar has tools enabling a user to easily create bookmarks and quickly access them. Bookmarks can also be created manually from the web interface, or by use of third-party tools such as Firefox extensions created for the purpose of managing …

Faves is a social bookmarking and networking software that installs a single browser button for users to “fave” a webpage, making a link to the page part of their Faves profile. Until October 2007, Faves was called Blue Dot.
While offering a service similar to the better-known del.icio.us, Faves has a wider range of functionality that encourages interaction with “friends” in rating the content of linked webpages. When a registered user visits their Faves home page, they see a summary of the bookmarks, called “Faves” by the company, that have …

Delicious (formerly del.icio.us, pronounced “delicious”) is a social bookmarking web service for storing, sharing, and discovering web bookmarks. The site was founded by Joshua Schachter in 2003 and acquired by Yahoo! in 2005. It has more than five million users and 150 million bookmarked URLs. It is headquartered in Santa Clara, California.
Delicious uses a non-hierarchical classification system in which users can tag each of their bookmarks with freely chosen index terms (generating a kind of folksonomy). A combined view of everyone’s bookmarks with a given tag is available; for …

StumbleUpon is an Internet community that allows its users to discover and rate Web pages, photos, and videos. It is a personalized recommendation engine which uses peer and social-networking principles.
Web pages are presented when the user clicks the “Stumble!” button on the browser’s toolbar. StumbleUpon chooses which Web page 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. Users can rate or choose not to rate any Web page with a thumbs up or thumbs …

Launched in September 2006, AddThis is the #1 bookmarking and sharing button on the Internet. AddThis has become the standard button for bookmarking and sharing. The AddThis button spreads your content across the Web by making it easier for your visitors to bookmark and share it with other people, again… and again… and again. This simple yet powerful button is very easy to install and provides valuable Analytics about the bookmarking and sharing activity of your users. AddThis helps your visitors create a buzz for your site and increase …

ShareThis provides a widget for easily sharing content found online with others through social networks, social news sites, and other online services. Users can also email content to friends with the widget.
The first version of the widget was launched in November 2007. The latest was launched in March 2008 and features tracking and usage reports for web publishers.