Data about the frequency of use of search terms on Google can be openly inquired via Google Trends and have been shown to correlate with flu outbreaks and unemployment levels, and provide the information faster than traditional reporting methods and surveys.
As of mid-2016, Google’s search engine has begun to rely on these deep neural networks.
Previous keyword-based methods of ranking search results, used by many search engines that were once more popular than Google, would rank pages by how often the search terms occurred in the page, or how strongly associated the search terms were within each resulting page.
The Page Rank algorithm instead analyzes human-generated links assuming that web pages linked from many important pages are themselves likely to be important.
Prior to Universal search, a standard Google search would consist of links only to websites.