From Buzzfeed:

Culture Buzz: The new way to say "no" is by simply not responding. The Silent No is perfect for business, romance, and family situations. It lets you stay positive in face-to-face encounters and avoids the awkwardness of sharing bad news. Did a loser ask you on a date? Having second thoughts about a business agreement? Or just too busy to deal with all the people who want something from you? Don’t respond and they will eventually get the message.

If this is a cultural trend, then I hate it.  It’s cowardly and weak.