Well at least YOU got a laugh out of that Yahoo goof. If you looked at the 5 day, you might have noticed that there was a corresponding spike in volume at 10:40am, but it was only 3 MIL shares. It might indicate some heavy buying to try and support $30, maybe some of that $5 BIL buyback money.
After seeing this message earlier today, I looked at the chart. It said "millions". I assumed Yahoo had already corrected the error. I just looked again and it now says "billions" again. Yahoo has got some hiccups.
All this reminds me of Senator Everett Dirksen's famous lament about Congressional spending, "A billion here and a billion there and pretty soon you're talking about real money."