Introduction

Social bookmarking is an activity performed over a computer network that allows users to save and categorize a personal collection of bookmarks and share them with others. Users may also take bookmarks saved by others and add them to their own collection, as well as to subscribe to the lists of others. - a personal knowledge management tool Social bookmarking sites are a popular way to store, classify, share and search links through the practice of folksonomy techniques on the Internet or Intranet. Other than web page bookmarks, we can find services specialized to a specific subject or format (feeds, books, videos, music, shopping items, map locations, wineries ...).

Social bookmarking sites are a popular way to store, classify, share and search links through the practice of folksonomy techniques on the Internet or Intranet.

Other than web page bookmarks, we can find services specialized to a specific subject or format (feeds, books, videos, music, shopping items, map locations, wineries ...).

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, 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.

Social bookmarking inspired the social news movement which included sites like digg, reddit, and the new Netscape portal.

Functional Overview

In a social bookmarking system, users store lists of Internet resources, which they find useful. These 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. 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

InShort
Social bookmarking is the practice of saving bookmarks to a public Web site and ‘tagging’ them with keywords. Bookmarking, on the other hand, is the practice of saving the address of a Web site you wish to visit in the future on your computer. To create a collection of social bookmarks, you register with a social bookmarking site, which lets you store bookmarks, add tags of your choice, and designate individual bookmarks as public or private. Some sites periodically verify that bookmarks still work, notifying users when a URL no longer functions. Visitors to social bookmarking sites can search for resources by keyword, person, or popularity and see the public bookmarks, tags, and classification schemes that registered users have created and saved.

• Activities like social bookmarking give users the opportunity to express differing perspectives on information and resources through informal organizational structures. This process allows like-minded individuals to find one another and create new communities of users that continue to influence the ongoing evolution of folksonomies and common tags for resources.
  
• 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, 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 SEO 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.
  
• By definition, social bookmarking is done by amateurs. There is no oversight as to how resources are organized and tagged. This can lead to inconsistent or otherwise poor use of tags.

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