South Korean company Cyworld claim that 90% of South Korean 24 to 29 year olds (a quarter of the total population) have a minihompy (miniature homepage) on Cyworld. One feature that makes it a bit different from blogs and other home page services is the 'miniroom', that users construct. At the bottom of the Cyworld website there are links to Taiwanese and Chinese versions, but the Japanese version link is not live, for some reason.
Hat tip to Doors of Perception.