 Acquaintances, by contrast, know people that we do not, and thus receive more novel information.Included in the definition of "absent ties", according to the American sociologist Mark Granovetter, are those relationships (or ties) without substantial significance, such as "nodding" relationships between people living on the same street, or the "tie", for example, to a frequent vendor one would buy from.Such relations with familiar strangers have also been called "invisible ties" since they are hardly observable, and are often overlooked as a relevant type of ties.