Microsoft, Yahoo Cross Swords on Windows Phone 7 Data Drain

Microsoft and Yahoo are trading blame for a Windows Phone 7 data-drain issue related to synchronization between Yahoo Mail and Windows Phone Mail Client.

Microsoft has blamed Yahoo Mail for a "data-drain" bug affecting a small subset of Windows Phone 7 devices. However, Yahoo seems intent on shoveling that blame right back on its rival-backslash-partner.

The fun originally began when an unknown subset of Windows Phone 7 users began complaining their devices devoured data even when not running applications or cruising the Web. Some of those users reported data consumption in the range of 30MB to 50MB within a 24-hour period.

On Jan. 20, Microsoft claimed an unnamed third-party application was responsible for the drain, and that it had taken all appropriate steps to make the application's developer aware of the issue. A few days later, Within Windows blogger Rafael Rivera performed a little dissecting of his own and claimed that Yahoo's IMAP (Internet Message Access Protocol) server ( was not responding correctly to Windows Phone's FETCH requests.

Following Rivera's Jan. 31 posting on the subject, Microsoft officially confirmed what it said was "an inefficiency" in the "synchronization of e-mail between the Windows Phone Mail client and Yahoo! mail." It offered a series of steps for Windows Phone 7 users to solve the issue, which involves changing Yahoo Mail's settings.

Yahoo, though, sees the whole issue as one-sided-as in, not Yahoo's problem.

"Yahoo! Mail is widely available on tens of millions of mobile phones, including those running on Apple iOS, Android, Nokia Symbian and RIM," read a Yahoo spokesperson's Feb. 1 e-mail to eWEEK. "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."

In addition, the spokesperson wrote, "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."

Microsoft is also planning a smartphone software update that will address a separate issue related to Exchange ActiveSync e-mail synchronization. Other updates, scheduled to arrive in coming weeks, will tweak application-loading speed and introduce a cut-and-paste feature. Currently available on GSM-based networks such as AT&T and T-Mobile, Windows Phone 7 will reportedly appear on CDMA (Code Division Multiple Access) networks such as Sprint and Verizon before the second half of 2011.

Despite their tempest-in-a-teapot over smartphone mail, Microsoft and Yahoo are joined in a search-and-advertising agreement centered on Bing powering Yahoo's backend search. Both companies remain locked in fierce competition with Google, which continues to dominate Web search, and whose Android smartphones and tablets boast an increasing market share.