Global Privacy Control (GPC) is a proposed specification designed to allow Internet users to notify businesses of their privacy preferences, such as whether or not they want their personal information to be sold or shared. It consists of a setting or extension in the user's browser or mobile device and acts as a mechanism that websites can use to indicate they support the specification.Essentially, GPC in Firefox tells the websites you visit "not to sell or share information about your browsing session on that website," although, notably, it doesn't appear to prohibit the collection of browsing data. According to Mozilla's support page about GPC, certain US states -- California, Colorado, and Connecticut are called out specifically -- mandate that GPC also be treated as a Do Not Track request, and in other areas, like the EU, UK, Nevada, Utah, and Virginia, GPC grants additional benefits on top of DNT, including opting out of targeted ads and sale of personal data.