This recommendation apparently only applies in areas where there is risk of building collapse. In the US, building collapse is unusual, unless the quake is exceptionally powerful.
Summary: Hiding under furniture ("Duck and Cover") may be a good choice in most American earthquakes, since we have better building codes and enforcement. If there is a risk of the building collapsing, though - if it's a very powerful earthquake - do NOT hide under furniture - hide NEXT to it. If you are outside, move to an open area away from falling debris and power lines!
As for me, I think I will identify "triangles of life" near me in daily life, but try to find ones that are actually also reasonably shielded from falling smaller debris.