We originally heard claims of Windows Phone 7 devices mysteriously sending out huge chunks of data almost a month ago, and now the culprit has finally been revealed: Yahoo! Mail. The company issued a statement today, blaming Microsoft's implementation of IMAP in WP7 for the data leakage. Yahoo! says it has provided Microsoft with a "near-term solution," although there was no ETA on when that fix will be made available. In the mean time, it's being suggested that those of you that use WP7 and Yahoo! Mail change your settings to download new mail manually and to only download mail from the last 7 days. The full statement from Yahoo! on the matter:
"Yahoo! Mail is widely available on tens of millions of mobile phones, including those running on Apple iOS, Android, Nokia Symbian, and RIM. The issue on the Windows Phones is specific to how Microsoft chose to implement IMAP for Yahoo! Mail and does not impact Yahoo! Mail on these other mobile devices. Yahoo! has offered to provide Microsoft a near-term solution for the implementation they chose, and is encouraging Microsoft to change to a standard way of integrating with Yahoo! Mail, which would result in a permanent fix."
I'm kind of surprised that it's taken this long to uncover the cause of WP7's data leaks, especially considering that a lot of users are on AT&T's limited data plans, but it's good to know that a fix is coming shortly. Many of you have reported experiencing some "phantom data" usage on your WP7-based phones in the past, so we'll be sure to keep you updated on the situation. Stay tuned!