Visitor interaction or inspection is a type of player interaction.
Players can visit each other's Estates/Camps and interact with structures and decorations by clicking on them (also called "knocking" in the game), thereby creating a bonus for both the interacting visitor (received immediately) and the owner (stored in the structure/decoration). A player can collect their visitors' boons by clicking on their own structures and decorations.
A player has a maximum of 50 free visitor interactions per day, and can use a maximum of 5 of these per friend. To exceed the overall or per-friend-limit, Golden-touch Hands can be used. Once a player has built the Castle, their daily free visitor interactions are increased from 50 to 100.