Baidu Japan announced a new service last month dubbed "Tieba" (pronounced te ieba
in Japanese, meaning "speaking of") now in beta. Tieba is a new set of SERPs that returns forums and social media results. If no forum or topic discussion is available then users are encouraged to start one.
Apparently the Tieba SERPs were one of the reasons for Baidu's popularity in China. The service has no rivals in the Japanese market that I know of.
The service has been available for a month now, and there appears to be a good amount of content. However most of it is centered around pop culture concepts rather than business. That may change if Japanese SEOs decide to target this. ;) Baidu press release about Tieba [baidu.jp...] in Japanese