With this Bookmark Locations On WP Maps extension, your site visitors can easy bookmark their favourite places / records in the listing that you are displaying with the WP MAPS PRO plugin.
An heart icon will be displayed in the listing and in the info-window also. Visitor will need to click on the heart icon to bookmark that as their favourite record in the listing. If visitors are logged in on your website and they bookmark their favourite places in the listing, it will be stored in database for their reference. And later when they visit your google maps page again, they will be able to view their favourite places. Bookmarked and non bookmarked places/records are represented by two different heart icons.