As is the nature of web publishing and ads found on websites, targeted ads are lucrative. Google Chrome’s Incognito Mode – and modes like it on other browsers – can be a good way to limit what kind of data you allow to be collected, since you’re temporarily signed out of any accounts you’re logged into.
That said, detecting that you’re using this mode is as simple as trying to use the “FileSystem” API. This API allows for sites to store files, either temporarily or permanently. It also happens to be disabled in Incognito Mode. According to an internal design document obtained by 9to5Google, the Chrome team intends to allow a virtual version of the API to run using RAM. This defeats the current Incognito detection method and wipes any stored data once Incognito Mode is closed.
The team also seeks to get rid of the FileSystem API altogether, since its primary use is to detect the usage of Incognito Mode. This will be especially true if they discover that no website uses the API for purposes other than detecting Incognito Mode. As for when this Incognito detection-thwarting mechanism will come into play, a developer involved in the project hopes that it can roll it out behind a flag in Chrome version 74, and have it enabled by default in Chrome 76. (Source: Google [1], [2] via 9to5Google)
