Point On Research conducted this survey, in Japanese, on Japan SNS in early June, with interesting results. The questionnaire targeted demographics, representing 50-50 sample of male to female and equal 25% ratio on the age split between teens, twenties thirties and forties, for feedback on platforms and access with Mixi the clear leader at 72% and mobile preferred to PC by more than 4 to 1 margin. Another note of interest shows that over 65% of the group indicate they are daily users!
See What Japan Thinks for handy tranlated tranlated version:
On the 8th of June 2009 exactly 800 people successfully completed a private mobile phone internet-based questionnaire. 50.0% of the sample were male, 25.0% in their teens, 25.0% in their twenties, 25.0% in their thirties, and 25.0% in their forties. Note that because this is a mobile phone-based sample, which judging by previous surveys means there will be an over representation of heavy mobile users, so the absolute percentages of mobile SNS users should be viewed in that light; the original text does indeed describe the sample as being “heavy users”.
Seron also has a good dig on survey for IC cash payments in Japan Here