During the four days of the surge, the email form on the home page collected 4 signups. The same form on the screen that says your browser cannot run this yet collected 1,457, about 8% of the people who saw it.
It makes sense once you see it. On the home page you have other things to do. On the wall you came to do something, you cannot, and leaving your email is the only move left. The ask works when it arrives at the moment it is useful to you, not at the bottom of a page.
So the home page ask moved up, directly under the places. There are new, quiet asks next to the loading cover and in the pause menu. Dismiss one and it stays dismissed, and signing up anywhere quiets all of them.
The same pass added a Share button in the pause menu and in photo mode. On a phone it opens your share sheet, with the frame attached where the sheet allows it. A shared link shows a card of that place, not a generic one.