The Clear Cooperation Policy is a National Association of Realtors (NAR) policy enacted in 2020 that states that:
Within one (1) business day of marketing a property to the public, the listing broker must submit the listing to the MLS for cooperation with other MLS participants. Public marketing includes, but is not limited to, flyers displayed in windows, yard signs, digital marketing on public facing websites, brokerage website displays (including IDX and VOW), digital communications marketing (email blasts), multi-brokerage listing sharing networks, and applications available to the general public.
Read the full policy here:
https://www.nar.realtor/about-nar/policies/mls-clear-cooperation-policy