Microsoft suspended a microblog-style site for Chinese users on Tuesday after the service was accused of copying programming code from Plurk, a Twitter rival popular in Asia.
Microsoft is looking into the allegations against MSN Juku, which a Microsoft joint venture in China hired a third-party vendor to develop, the company said in a statement. The service, still in beta and launched last month, could not be accessed on Tuesday. Microsoft promised to release further information as it learned more.
Plurk did not reply to e-mails or phone calls on Tuesday.
Online social networking is increasingly popular in China and Microsoft was just one of several big companies looking to tap the market, though Twitter and some of its local-language rivals have been blocked for months in the country on political grounds.
(Dan Nystedt in Taipei contributed to this report.)