In 2012, internet search and social media are beginning to converge. Search engine operators have discovered that social media provides data about people that can be used to improve search results and target adverts more productively to specific users or groups of users.
Whenever somebody enters a search term into a search engine, algorithms evaluate the relevance and value of websites and pages within that search engine index. The page and site deemed most valuable and pertinent by the algorithm appears at the top of the search results, and other pages and websites appear in descending order according to their calculated relevance and value. At the same time, adverts which are attached to specific search engine queries are displayed to the search user on the understanding that, to take one example, searching for "buy car insurance" indicates a desire to buy car insurance.
How search engine algorithms determine relevance and value is difficult to prove. Because there are so many different metrics used within search engine algorithms, the details of which are often kept secret for commercial reasons, it can be difficult to link cause and effect when analysing the search engine performance of a particular website. Some estimates place the number of different ranking metrics higher than 200, making the task of disentanglement a troublesome one.
However, it is certain that link profiling features heavily within search engine ranking algorithms - the more inbound links received by a site, the more authority accrued by that site, in much the same way as you might determine academic influence by the number of subsequent publications that reference an earlier work. Through rigorous testing, some analysts have compiled lists of further probable ranking metrics, and one of these is page-level social signal data. Many authorities deem it likely that social signal data will increase in significance over the coming year.
Social signals help to solve several problems for search engines. Although backlink volume and quality has a positive correlation with perceived relevance and value in the eyes of human observers, there are instances when a website might link to another page simply for the purpose of ridicule. In this case, the standard practice of counting inbound links as "votes of confidence" for the quality of the content at the link destination could produce a misleading outcome. A Facebook 'Like' and a Google+ '+1' are far less ambiguous and can hardly be interpreted as anything but a sign of approval.
Perhaps more importantly, in the context of the web as a commercial arena, social signals link individual identities with expressions of approval. A Facebook 'Like' carries not only an expression of approval but also the profile and interests of the person who likes the content. With the increasing level of integration between Google+ and Google search, we can already see the impact of personal data in the new Google Search Plus Your World service - content that has been approved by many acquaintances will appear closer to the top of the search results delivered to an individual who is signed into a Google profile.
Search engines are moving away from making broad generalisations about people and moving towards delivering a more personal experience that takes into account the human relationships that inform perceived value. In time, this may contribute to the gradual fragmentation of the search engine optimisation industry as we understand it today. If personalised search becomes the standard form, backlink volume and quality (and other 'general' metrics) may become less important than the preferences of an individual.