http://en.wikipedia.org/wiki/Civilization_(computer_game)
"The historian and anthropologist Matthew Kapell has published an essay critical of the Civilization series. It suggests that the game uses unique American myths of progress and the frontier in culturally elitist fashion. (“Civilization and its Discontents: American Monomythic Structure as Historical Simulacrum.” Popular Culture Review Vol. XIII, No. 2 (Summer): 129-136.)
“This high level of interest has spawned a number of free software versions, such as Freeciv and C-evo, and inspired similar games by other commercial developers, as well."
according to gameDailyBiz, in Dec.2005 civ was the third highest selling video game for the week.
see also http://civilization.wikia.com/wiki/Main_Page
Civilization (original game) - Civilization
http://civilization.wikia.com/wiki/Civilization_%28original_game%29
“...The degree of popularity may be discerned from the observation that in an industry where the lifespan of a product typically averages 6 months or less, this game (by means of all its versions and updates), has endured for over a decade and a half, with product being offered for sale the entire time in retail stores.”
http://worldhistoryconnected.press.uiuc.edu/4.2/whelchel.html says “civ iii” has sold over 3 million copies, attributed to www.theesa.com (entertainment software assoc.)
http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20070328005486&newsLang=en says civ iv has sold over 1.5 million copies (since oct 2005 release) in article dated 28 mar 2007