The owner of a coin can post updates as the coin from the Posts tab of its coin page. An update is up to 280 characters with up to 4 images. It shows the coin's logo and a Creator update label. Tick Also in the home feed to share it more widely.
The coin page also posts automatic updates for the launch, graduation and battles. Owners can turn those off on the edit page. Battles, UpVotes and league pushes are the other ways to get attention.