Google is testing showing a "Post" button in the carousel of buttons in the Google Business Profile local listing panel. So when you view your owned business in Google Search, you may see a "Post" button near the call, directions, share, and save. There is also an "Edit" button there.
Typically, those buttons would be above the listing, to manage your local business in the search interface using the new editor. But Google I guess is testing placing "Posts" and "Edit" (not sure if Edit is new) in that bar.
Here is a screenshot from Justin Mosebach who posted it on X:
I do not see it myself and I think Google tests this on and off for some profiles.
Here is a video of it in action:
@rustybrick this "+ Post" button on Google Maps *might* be new or somewhat new. pic.twitter.com/mE1yCTK2kR
— Justin Mosebach (@jlmosebach) April 12, 2024
Forum discussion at X.
