Google News has already become the most trusted and widely used source of information for researchers around the world.

According to ResearchGate, web search engines are probably the most important means of retrieving information for web-based information systems. Among the major search companies, Google has gained a reputation as one of the leading and most popular search engines. In 2006 in the USA there were 91 million queries searched daily on Google alone. The total number of queries searched daily on all search engines was 200 million (Sullivan, 2006).

Besides being fast and user-friendly, Google’s popularity is mostly due to the relevance of the retrieval results for a typical query. In other words, recall and precision are often high for Google’s search results. By implementing the PageRank algorithm (Brin and Page, 1998), Google introduced citation models in web search in order to improve the quality of search results.

Tracking web citations became possible because web search engines are probably the most important means of retrieving information for web-based information systems. Among the major search companies, Google has gained a reputation as one of the leading and most popular search engines. In 2006 in the USA there were 91 million queries searched daily on Google alone. The total number of queries searched daily on all search engines was 200 million.

Besides being fast and user-friendly, Google’s popularity is mostly due to the

relevance of the retrieval results for a typical query. In other words, recall and precision are often high for Google’s search results. By implementing the PageRank algorithm, Google introduced citation models in web search in order to improve the quality of search results. Tracking web citations became possible because of the hyperlink structure of the web resources. The rich structure of the web link graph has enabled the estimation of the global as well as local popularity of the documents on the web.

Google has been constantly creating new services such as Google Books and Google Scholar to cover special contents.