A recommendation is a type of post that provides a suggestion to another person.
Facebook has a UI for requesting recommendations from friends within a certain geographical area.
The user requesting recommendations first specifies what sort of recommendations they want and where they should be geographically.
The user can then add the recommendations request to their timeline.
An example of a recommendations request in the timeline.
Other users can then search for places to add as recommendations with an add button and search field in the top right of the map.
Recommendations are then saved on the map and appear as a pin with a popup.
In an indieweb context this sort of functionality is likely to be achieved by accepting a Webmention on a post.