[whatwg] Private browsing vs. Storage and Databases

Bil Corry bil at corry.biz
Wed Apr 8 10:02:13 PDT 2009

Brady Eidson wrote on 4/7/2009 7:24 PM: 
> A commonly added feature in browsers these days is "private browsing
> mode" where the intention is that the user's browsing session leaves no
> footprint on their machine.

I must admit, I haven't ever used "private browsing" but my expectation of such a feature would extend beyond erasing a local footprint -- it would also provide privacy by *not* sending existing cookies, providing access to existing LocalStorage, etc.  Is there really a use case for wanting to show up at a site as yourself, but not have any footprint of the visit saved locally?  If anything, it would make it easier for someone to use your computer, visit aites as you, and hide their activities of what they did as you.

As a user, I'm most attracted to Chrome's implementation -- a new blank user profile that gets entirely erased when finished (using option #3).  I like it for the following reasons:

	(1) Full privacy - a site will not know who I am based on existing cookies, etc.
	(2) Makes detecting "privacy mode" (near?) impossible since the browser behaves identically to "normal mode" (e.g. no errors coming from LocalStorage).
	(3) Makes it very easy for the user to understand -- nothing is saved in this mode, including LocalStorage.
	(4) Sites continue to work as normal (e.g. no errors coming from LocalStorage).

- Bil

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