"The Overview Effect" --- a term coined by book author Frank White in 1998 --- is the examination of the impact on human society to actually begin to see itself as a whole planet Earth from space. The globalization of the visualization has had a macro-impact on culture, economics, politics, and very human social fabric on Earth the past half-century.
Not readily recognized or acknolwledged in day-to-day human activity, "The Overview Effect" of the Space Age is real even at the micro-scale of human activity in our music, publications, communications, and mental comprehension compounded by the Information Age.
As the human quest to Return to the Moon, expand the X-Prize Cup, explore more of Mars, view more Hubble Space Telescope images, build private space stations and take tourist spacewalks all continue, "The Overview Effect" is expanding. The adventure and spirit is set to proliferate into a new profound era for the youngest among us in the 21st century. We live in a time when an new Earth-like planet may be soon found within the Milky Way Galaxy.
As one science teacher recently related, young elementary school students of 'Gen-Y' are more impacted today by the visualization revelations of our galaxy than that of the whole Earth. The younger among us are coming to the realization that "what goes-up ...." can continue! :)