Google uses a system of categorizing terms that are identified as synonymous or frequently associated with each other to interpret the meaning of content.
This system is called Latent Semantic Indexing and this part of the algorithm assigns a “relevancy score” to a web page’s content, and as such, is a major factor in determining Google search results for any given query.
Google highlights terms in bold which have been tagged as synonymous or frequently associated to the terms in your search string.
For example, the term “auto” is synonymous with the term “car,” therefore, in Google’s algorithm, auto = car in terms of relevancy. Note the emboldened term “car” in the Google search results for the phrase “Esurance auto insurance” below:
Google has determined, based on extensive analysis of search behavior, that the term “sucks” has a relevant home in the American Lexicon. Check out the results for the Google search “Mystic Lake Casino sucks:”
For Google, Sucks = Reviews.