Given the obvious similarities Microsoft quickly pulled the service to start an investigation, and less than 24 hours later revealed that a third-party vendor working with Microsoft's MSN China joint venture acknowledged a portion of the code that it provided was indeed copied.
Microsoft was apologetic in its note, saying it was never their intent to steal the work that others in the industry have done, but that may not be enough to get them out of the woods. According to Plurk, a lawsuit is one of many options they have and are still considering.
Ironically the company has been working hard in China over the years to try to prevent the piracy of its own software. The company is suspending access to Juku indefinitely and says it will be working with MSN China to examine development practices and applications provided by vendors.