Are Europeans Really Not Using Twitter?
thenextweb.com
thenextweb.com
It makes sense that if the usage is very low almost to the point of nil than any growth is going to seem "staggering". i.e. If you go from 1 person using it to 2 people using it then you've just grown 100%!!!
I'm guessing there's a few lesser spoken European languages in that "all others" category.
[1]http://www.comscore.com/Press_Events/Press_Releases/2011/4/T... [2]http://blog.sysomos.com/2010/01/14/exploring-the-use-of-twit...