So Yahoo's Mail app was determined to be the culprit in the big Windows Phone 7 data bloat problem. Now the company has issued a statement of apology, sort of.

"Tens of millions of people check their Yahoo Mail from their mobile device each day, and we know they want their mobile mail experience to be fast, rich, and real-time. While our default settings on all mobile platforms realize this approach, we have determined that an inefficiency exists in the synchronization of e-mail between Windows Phone Mail clients and Yahoo Mail, which can result in larger than expected data usage for some users."

So that's the apology. But in another statement to CNET the company said:

"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."

Okay, so they sort of put the blame back on Microsoft but at least they've figured out the problem. Now maybe one of the companies will fix it.