Facebook announces great Q2 numbers. And the stock is?

Facebook just announced its Q2 numbers.
And like Twitter, its stock is down circa -4%....

Revenue of 4.04 Billion usd is +39% year on year! 

968 million DAILY actives users and that's up +17% year on year!

Only about 17% of those users are USA/Canada so Facebook's reach is more global.

About 65% of Facebook active monthly users are now daily users so it's being used more often.

And daily users are using it on average, for 46 minutes a day.

Facebook generates 1.5 Billion searches a day.
And users are sharing +40% more video than they were.

Margin has dropped from 48% to 31% but that's on the back of increased costs through investment which to be fair, Facebook warned it was doing.
They have 2 million advertisers.

Video too, is driving their Ad growth said Sandberg because it's now more targeted.

So overall, that's a pretty great performance no matter what way you look at it. Huge increases in Revenue, Daily active users, better global spread, longer dwell times, video drivers, new investment, more advertisers....and the stock is what? 
Down? 
Explain that because it's making no sense. 
At all.