All of this is speculation, but deduced from combing through this thread and
After 3pm?.
Stanford's notification emails, according to reports in the forums, look they started to go out at about 3:55 pm Pacific time. The LAST confirmation of the receipt of such an email came at 4:20 pm. That means that the email engine ran for only about 25 minutes and then must have crashed. We don't know how many records (out of the 25,000 to process) it could have run through in just 25 minutes, but I would seriously doubt that it's even half.
As to when they'll notice the crash and fix it, I can't say. I just know that there are a lot of frustrated Stanford applicants and families out there right now.
I also seriously doubt that the records were processed in any discernible order (geography, category, etc.). Records of all three types (rejections, acceptances, and waitlists) certainly did go out. Otherwise, I don't see a pattern in the data, but admittedly, I haven't had the time to do a rigorous analysis either.