There was a great talk at SRECon Europe 2015 about how Facebook scales out their load balancers: https://patrickshuff.com/building-a-billion-user-load-balanc...

Shows how many levels of scaling are required to serve traffic at large scale.

yup, i thought it was related to the GlobalSign cert issue (since I use a cert from them) but isn't... and here I just purchased a replacement from Comodo. lol