Hospitality
Contemporary usage seems different from historical uses that lend it personal connotations. Today's hospitality conjures images of throwing good parties, gracious hosts entertaining, etiquette, Martha Stewart or even talk shows, or, the hospitality services industry as it relates to the entertainment and tourism business. On the other hand, hospitality used to be, and still is, a serious duty, responsibility, or ethic. Hospitality ethics is a discipline that studies this usage of hospitality.
In the western context, with its dynamic tension between Athens and Jerusalem, two phases can be distinguished with a very progressive transition: a hospitality based on an individually felt sense of duty, and one based on "official" institutions for organized but anonymous social services: special places for particular types of "strangers" such as the poor, orphan(s), ill, alien, criminal, etc. Perhaps this progressive institutionalization can be aligned to the transition between Middle Ages and Renaissance (Ivan Illich, The Rivers North of the Future).

Contemporary usage
In Middle Eastern Culture, it was considered a cultural norm to take care of the strangers and foreigners living among you. These norms are reflected in many Biblical commands and examples, for instance: [1]
Perhaps the most extreme example is provided in Genesis. Lot provides hospitality to a group of angels (who he thinks are only men); when a mob tries to rape them, Lot goes so far as to offer his own daughters as a substitute, saying "Don't do anything to these men, for they have come under the protection of my roof." (Genesis 19:8, NIV).
The obligations of both guests are stern. The bond is formed by eating salt under the roof, and is so strict that an Arab story tells of a thief who tasted something to see if it was sugar, and on realizing it was salt, put back all that he had taken and left.

Biblical and Middle Eastern conceptions of hospitality
Hospitality as a cultural norm or value is an established sociological phenomenon that people study and write papers about (see references, and Hospitality ethics).

See also
Of Hospitality - Jacques Derrida, translated by Rachel Bowlby (Stanford: Stanford University Press, 2000).