From poster +‎ -ing.

postering (usually uncountable, plural posterings)

1. The putting up of posters.

   The musician's new album was promoted with a postering campaign.

   • 2006, Eran Razin, Patrick J. Smith, Metropolitan Governing: Canadian Cases, Comparative Lessons:

     There were marches, parades, posterings, leafleting, speeches by the politicians in the opposition parties, filibustering in the legislature, threats of legal challenges by all the cities and by citizens, and referendums in each of the six cities.

• G proteins, G-proteins, progestin, reposting