More Cookie Notices…

One of the cookie acceptance notices I’ve started noticing on first visits to several sites lately comes from TrustArc:


This categorises cookies into three classes — required, functional and advertising — and lets you make decisions on whether to accept those cookies at the category level or the individual provider level if look at the Detailed Settings:


However, opting out at the category level doesn’t necessarily mean you have opted out of all the cookies provided in that category:


So whilst I like things like the TrustArc display in principle, it would be nicer if it also had a percentage bar display, for example, showing the percentage of cookie providers that were successfully opted out from in that category?

I’m not quite sure how cookie opt-outs work. I can see how it’d work on the user side – e.g. follow a link provided by someone like IgnitionOne – to a page that sets opt-out cookies in your browser, but how about a publisher setting the opt-out from a third party on your behalf? This description — OpenX – how the cookie-based opt-out mechanism works — suggests that the publisher calls a link and then “OpenX sets the user opt-out cookie and performs a test to see that the user accepted the cookie“, but how do the bits of data flow and what state or flags are set where? Another one to add to the “I don’t understand how this actually works; try to find out at some point” list…

PS From the Forbes website, a slider to control cookie levels: