We will probably never see any official acknowledgement that the Yahoo data drain bug has been resolved, but based on personal experience I am fairly certain that this problem is now history. I have tracked my data usage through this past month’s cycle which ends today, and it appears that as of February 16th something changed. Note that I am using Wi-Fi 24/7 and don’t do a lot of data browsing/streaming while away from my connection.

Between January 26th and February 16th I averaged 38.8MB of data per day, with a high of 63MB and a low of 10MB. Total data usage for that period: 832MB. Sometime during that period I changed my sync frequency from every 15 minutes to every 30 minutes, which resulted in a small reduction of data use. I also cleared out my inbox several times, to under 100 messages, which had an immediate impact on total data usage, hence the wide range between high/low data days. From February 16th to February 25th, total data usage has been 33MB, or 3.7MB per day, with a high of 5MB and low of 1MB. I also resumed the sync every 15 minutes scenario five days ago and have not cleared my inbox, which now stands at 731 messages, in about 12 days.

So is this info conclusive. I don’t know. I do know that AT&T did change something last Sunday (February 20th) as when I attempted to check my data use I was told to check back after 5pm as the system was undergoing maintenance. But I had already experienced three days of 4MB or less prior to that day. Based on the first two thirds of the month I was headed towards 1.2GB data for the month, which has been about my average since last November (only setup a Yahoo account in early January and went Wi-Fi 24/7 in late December). Based on this last third of the month though, looks like I may be around the 115MB per month range, without any real change in habits. That’s significant. I have also noticed an incremental improvement in battery drain, which would be expected with much less data processing occurring in the background. Don’t know if there is anything else nibbling on 3G data within the WP OS but wouldn’t be surprised if there was. Thank you Microsoft and Yahoo for resolving this issue, that  never really happened. Right.