Via @eMarketer, #Facebook's net US #digitalad revs +4.9% Y/Y to $31.43B, $FB's share of US #digital ad mkt = 23.4%, +0.7% Y/Y. #digitalmarketing #ecommerce #mcommerce #retail #retailmarketing #digitaladvertising #PPCMarketing #SEO #SEM $GOOG $AMZN $MSFT