With reference to the Windows Phone 7 data usage / leak issues, where its WP7 mobile operating system was sending, by at least one account, up to 50GB of unidentified data per day, unprompted by the user, Microsoft has responded with a statement.
In a statement to to Seattlepi, Microsoft said:
We have determined that a third-party solution commonly accessed from Windows Phones is configured in a manner that potentially causes larger than expected data downloads. We are in contact with the third party to assist them in making the necessary fixes, and are also pursuing potential workarounds to address the configuration issue in case those are needed. At this point in our investigation, we believe this is responsible for most of the reported incidents.
We are investigating additional potential root causes for the remainder of the reports.
A small (low single-digit) percentage of Windows Phone customers have reported being affected.
We are continuing to investigate this issue and will update with additional information and guidance as it becomes available.
Do note that they attributed the problem to “third-party solution”, which may be a third party app OR a third party module inside some WP7 application.