Example semantic class match between a web page about rainbow fish (a type of
tropical fish) and an advertisement for tropical fish food. The nodes “Aquariums”, “Fish”,
and “Supplies” are example nodes within a semantic hierarchy. The web page is classified
as “Aquariums - Fish” and the ad is classified as “Supplies - Fish”. Here, “Aquariums” is the
least common ancestor. Although the web page and ad do not share any terms in common,
they can be matched because of their semantic similarity