Social search engines-Pros and cons

In May 2009, worldwide, some 1.1 billion people (age 15 and older) access the Internet, either from their home or office. Out of those 1.1 billion people, (65 % of the world’s Web audience) visited minimum one social networking site during the month, making it two-thirds of the global Internet users who  will access social networking websites.
The term social search began to emerge between 2004 and 2005.Social ranking can be considered to derive from googles page rank algorithm.
Page rank algorithm assigns importance to web pages based on analysis of the link structure of the website, Page rank is relying on the collective judgement of webmasters linking to other content of the web.
Link structure of the webpages was given less importance and quality links have be given importance
In social searches each result has been selected by users.
Influence of a network of a trusted individuals provide an indication about a particular thing whether a particular result was good or bad.
The concept of human judgement was introduced and each webapge has been viewed and approved/ endorsed by couple of people.This opinions are shared with people.
Webpages are found to be relevant from the website visotrs point of view, not for the webmaster or for the  author.
Social search engines are constantly getting feed beek and their updation of the reuslts are current than the normal search engines.
Disadvantages of social search engines
Risk of spam as the users can directly add results to the social search engine there is risk that some users could insert search spam content directly into the search engine
How to prevent this type of scam is a big problem because the social search engines have to detect the validity of users contribtuion,whether it agrees with other trusted users.
Long tail of search are conducted infrequently.A social search engine relied on users filing in all the searches. An algorithmic search engine can rely on machines to crawl and index the entire web.
Morever social search engines may not be able to get correct conclusion about the ranking of a website as the users.