Why is "internationalization" shortened to "i18n"?

.

            1    1  1
   1---5----0----5--8
 i|nternationalizatio|n  == i18n

            1
   1---5----0
 l|ocalizatio|n          == l10n

See also http://www.w3.org/2001/12/Glossary#I18N.

http://en.wikipedia.org/wiki/Internationalization_and_localization

18 stands for the number of letters between the first i and last n in internationalization, a usage coined at DEC in the 1970s or 80s