[Grid-wide experiences]

The Lab did announce back in March that user-created gridwide experiences are coming.  See 

Number 8 on the list of upcoming features was this:

Quote

Gridwide Experiences - Currently, Creators can use the increased scripting capabilities of an Experience only in a region or parcel whose owner has explicitly enabled their Experience. One of the new Premium abilities will be an Experience that is enabled anywhere on the grid unless the landowner has blocked it.