Status

(work in progress)

Problem Summary

In short: let the UA's "clear cookies" function also clear Flash's local storage.

More precisely: delegate calls to the UAs "clear privacy information" to plugins, allowing them to clean up their locally stored data as well.

Type	Firefox	IE	Opera	Safari	Chrome
Browsing History	yes	yes	yes	yes	yes
Download History	yes	yes	yes	yes	yes
Form History	yes	yes	?	yes	yes
Search History	yes	?	?	?	?
Cookies	yes	yes	temporary/all	yes	yes
Cache	yes	yes	yes	yes	yes
Active Logins	yes	yes	"password manager"	yes	yes
Site Preferences	yes	?	?	?	?

In addition, IE has "InPrivate Filtering Data" (what is this?)

In addition, Opera has "delete password protected pages and data" and "bookmark visited times".

In addition, Safari has "webpage preview images", "website icons" and "top sites"

Here's an attempt to categorize these a bit more abstractly:

local data stored by the server / web application (cookies, HTML5 local storage, Flash/Silverlight local storage)

settings specific to a site (for instance, preferences with respect to privacy, script disabling...)

Parameters	Firefox	IE	Opera	Safari	Chrome
Time Range	yes	no	no	no	yes
By Site	yes (context menu in history)	??	??	??	??

In particular, Lloyd Hilaiel proposed an alternate approach where plugins would store everything in a standard filesystem based layout, so the UA itself can do the clearing. See https://mail.mozilla.org/private/plugin-futures/2010-January/001156.html