Graph data
From ActiveArchives
Mathematical concept of data (information) represented as items and relations. In semantic web terms, the relations themselves are proper items thus forming "triples" of information of the form subject, predicate (the relation), and the object.
Webpages on the web are an important form of graph data (when seen as pages with links between them). Social networks are also an increasingly prevalent form of "graph" data (users as nodes and social relationships / tags defined between them.