2010/1/25 Veronique Kessler vkessler@wikimedia.org:
Hello,
Thanks for the comment. The "mm" signifies millions which is the amount the timeline is representing, $6 million from 125,000 donors globally. If we were to replace it with one "m", that would signify only $6 thousand.
See also: http://wiki.answers.com/Q/What_is_abbreviation_of_million
"M" before the abbreviation of a unit means 1,000, but on its own it is far more commonly used to mean 1,000,000. "m" never means 1,000 - it means 1/1,000 when used with the abbreviation of a unit, but on its own it usually means 1,000,000 too.