David Eduardo wrote:

Most stations that play currents add new songs with a certain regularity.
These are always songs listeners have never heard, since promo copies, even
with the internet, get to radio before anyone else.

Stations try to find songs that will sount right for the format but will
also give variety. Very often on the three separate times I have filled in
as acting PD of an LA AC, I have looked at what we are playing as currents
and then looked at potential adds for songs that do not sound too much like
the bulk of the list. That means looking for songs that add variety and
differentiation.

The magic doesn't happen in the top markets. Places like Phoenix and
San Antonio are much more cutting edge. I played a test pressing of "I
Can See for Miles" that was delivered by courier on a Saturday night
without even asking McMahon's permission first.