Who’s Involved
The first element at stake is the website you visit. It sends the request for geolocation information. Then, there is the web browser, which is the side that receives the request to deliver location information to the website requesting it. Then, there’s the third party, which is the provider of your location and computes it as soon as it's requested.
The Privacy Issue
Solid risks are resulting from the centralized approach of gathering and sending location information. The use of the unique identifying information of the user to link the location requests can lead companies to build a mobility path and pattern of a certain user (where he usually goes to every day, shops he visits, roads he takes, among other information). This can be concerning because it can provide information on endpoints like workplace or home locations of the user and eventually lead to his full identification.
