Knowledge bases of entities and relations (either constructed manually or
automatically) are behind many real world search engines, including those at
Yahoo!, Microsoft, and Google. Those knowledge bases can be viewed as graphs
with nodes representing entities and edges representing (primary)
relationships, and various studies have been conducted on how to leverage them
to answer entity seeking queries. Meanwhile, in a complementary direction,
analyses over the query logs have enabled researchers to identify entity pairs
that are statistically correlated.