On Sunday, August 20, 2017 at 11:28:18 AM UTC-7, bitrex wrote:

A suitably advanced gregarious civilization capable of directing
"trumpet blasts" like that probably already has sufficiently powerful
space-based imaging to directly look the planetary surfaces of any
inhabited worlds within say 50 light years down to maybe several
hundreds of meters resolution, evaluate the civilizations they see
there, and decide whether they look like a species worth contacting, or not.

STILL PRETTY QUIET 'ROUND HERE

The possibilities of gregarious extraterrestrials have been explored
well in fiction. In Clarke's '2001', ...2010, 2061, "3001: The Final Odyssey"
he suggests one-way communication to young intelligences, and
general encouragement, at the behest of a distant ancient E.T. actor.

Stanislaw Lem's "Fiasco" is a more realistic treatment: we've just barely
arranged communication with a couple of Earth species, but the
long-lived social animals like great whales, elephants, aren't really talking
to us. What would they say?