Social bookmarking

Social bookmarking is a way for internet users to store, classify, share and search Internet bookmarks.

Introduction

On a social bookmarking system or network, users store lists of Internet resources that they find useful. These lists can be accessible to the public by users of a specific network or website. Other users with similar interests can view the links by topic, category, tags, or even randomly.

Other than web page bookmarks, services specialized to a specific subject or format - feeds, books, videos, shopping items, map locations, wineries, etc. - can be found.

History

The concept of shared online bookmarks dates back to April 1996 with the launch of itList.com. Within the next three years online bookmark services became competitive, with venture-backed companies like Backflip, Blink,^{[citation needed]} Clip2, Hotlinks, Quiver, and others entering the market. Lacking viable models for making money, most of this early generation of social bookmarking companies failed as the dot-com bubble burst.

In 2005 and 2006, social bookmarking sites, such as del.icio.us, Diigo, Furl, Ma.gnolia, Netvouz, and StumbleUpon became popular. Sites like reddit, Digg, Newsvine, and the new Netscape portal apply social bookmarking to news items. In 2007, IBM announced plans to enter the social software market.

Functional Overview

In a social bookmarking system, users store links to web pages that they find useful. These link lists are either accessible to the public or a specific network, and other people with similar interests can view the links by category, tags, or even randomly. Some allow for privacy on a per-bookmark basis.

They also categorize their resources by the use of informally assigned, user-defined keywords or tags (see folksonomy). Most social bookmarking services allow users to search for bookmarks which are associated with given "tags", and rank the resources by the number of users which have bookmarked them. Many social bookmarking services also have implemented algorithms to draw inferences from the tag keywords that are assigned to resources by examining the clustering of particular keywords, and the relation of keywords to one another.

Its increasing popularity and competition have extended the services to offer more than just sharing bookmarks, such as rating, commenting, the ability to import and export, add notes, reviews, email links, automatic notification, feed subscription, web annotation, create groups and social networks.

Automatic notification

Since the classification and ranking of resources is a continuously evolving process, many social bookmarking services allow users to subscribe to web feeds (see Atom or RSS) based on tags, or collection of tag terms. This allows subscribers to become aware of new resources for a given topic, as they are noted, tagged, and classified by other users.

Advantages

This system has several advantages over traditional automated resource location and classification software, such as search engine spiders. All tag-based classification of Internet resources (such as web sites) is done by human beings, who understand the content of the resource, as opposed to software which algorithmically attempts to determine the meaning of a resource. This provides for semantically classified tags, which are hard to find with contemporary search engines.

Additionally, as people bookmark resources that they find useful, resources that are of more use are bookmarked by more users. Thus, such a system will "rank" a resource based on its perceived utility. This is arguably a more useful metric for end users than other systems which rank resources based on the number of external links pointing to it.

Disadvantages

There are drawbacks to such tag-based systems as well: no standard set of keywords (also known as controlled vocabulary), no standard for the structure of such tags (e.g. singular vs. plural, capitalization, etc.), mistagging due to spelling errors, tags that can have more than one meaning, unclear tags due to synonym/antonym confusion, highly unorthodox and "personalized" tag schemas from some users, and no mechanism for users to indicate hierarchical relationships between tags (e.g. a site might be labeled as both cheese and cheddar, with no mechanism that might indicate that cheddar is a refinement or sub-class of cheese).

Social bookmarking can also be susceptible to corruption and collusion. Due to its popularity some users have started considering it as a tool to use along with Search engine optimization to make their website visible. The more a web page is submitted and tagged, the more chances it has of being found. Spammers have started bookmarking multiple times the same web page and/or each page of their web site using a lot of popular tags, hence obliging the developers to constantly adjust their security system to overcome abuses. Because of this some social bookmarking websites were forced to add CAPTCHA protection against spam, which caused some problems for people who use social bookmarking for non-spamming purposes.

Free implementation

Free (GNU GPL) implementation of social bookmarking tools exist, see Connotea from Nature Journal's Software Group.

Chipmark, Unalog and many more are also released under the GPL. Other services such as Warichu are free to use and contain open source modules (namely Collaborative Chew and Sticky Chew.)

Recently a number of services have been created using pligg.

Footnotes and references