When you share a marker the following personal data is sent from your smartphone to the GeoAR.it website :-
Latitude and longtitude coordinates of the marker - These are needed so that the markers can be accurately placed in the correct geographical location in the app of the people you choose to share the marker with. This data is encrypted in the database.
Name of the marker - This is needed so that people viewing your markers will be able to see the name you gave your marker. This data is encrypted in the database.
Share minutes - This is needed so that the website can auto delete expired shares and the app can determine when the share code will expire. Note: Sharing a marker set to 0 minutes will delete all previous share codes for the marker.