MacDonald Mobile Coupon
MacDonald's mobile coupon subscriber has marked 5MM according to its press release.
http://www.mcd-holdings.co.jp/news/2007/company/20070928.html
Since they have launched the coupon website in 2003, they record 1M subscriber in Oct 2006.
Service has been used mosty by teens and the ttl number of those teens figured as much as 1/5 of high school student in Japan.