"Microsoft takes intellectual property seriously, and we are currently investigating these allegations," company spokesman Mark Murray said in a statement. "It may take some time due to the time zone differences with Beijing."
Earlier on Monday, Canada's Plurk went public with charges that Microsoft's Juku service "rips off" the look and feel of its microblogging service and also appears to use more than 80 percent of the same code, all without permission.
"Imitation may be the sincerest form of flattery, but blatant theft of code, design, and [user interface] UI elements is just not cool, especially when the infringing party is the biggest software company in the world," Plurk said on its blog.
Plurk said it is still evaluating what to do in the case.
"We're not entirely sure but we are exploring our options," Plurk said. "We have been seeking advice from respected colleagues, responding to press inquiries and gathering facts on the timeline of events and parties involved here to understand why and how this took place."
It's the second time in recent weeks that Microsoft has been accused of lifting other's work in its products. Last month, the company was forced to pull down a tool for loading Windows 7 onto Netbooks after allegations that the product improperly included open-source code. Microsoft later apologized and last week re-released the tool under the GPL open-source license.