Apparently whatever I am seeing in the serps (logged out) is simply an illusion.
This is what's baffling me. I'm seeing the same thing as @backdraft7. In fact, we've had some really awesome, positive increases in some competitive keyword positions over the past couple of days (confirmed by third party services - not just me checking rankings). We should be getting flooded with traffic - but we're not. Yesterday was our worst Sunday in many years (and Sunday is usually our strongest day).