Is Microsoft Plotting A Yelp Competitor Named Postbox?

Earlier this year, Bloomberg BusinessWeek reported that Microsoft , not just Google , made a serious attempt to acquire business directory and reviews site Yelp . According to "two people involved in the negotiations", the Redmond software giant even bid as high as $700 million for the company. Yelp instead opted to remain independent, for better or worse. Google is attacking it with Places and Hotpot . And now some information has surfaced that indicates Microsoft could be planning a Yelp rival as well.