The Kardashians Radio Silent On Rob's Engagement

The Kardashians live and breathe on social media ... but in the 12 hours plus since Rob and Blac Chyna's engagement not a single tweet, Instagram post or Facebook update about the news.

Zilch.

Snapchat? Nada.

They've all been on social media posting but have made no mention of the engagement.

For a family that thrives on the millions of followers, they've not congratulated the family's only son and brother.