Cookies and dynamic pricing

[Guest]

There has recently been bit about this in the media. There are suggestions that some sites charge more when they detect that you are using an Apple Mac (because they assume that if you have an Apple Mac then you must be loaded!).

The trouble is that cookies are used all over the place and some are benign. Therefore suggestions to clear cookies at the end of a web session can be counter-productive. My solution is to reserve one browser (I chose Firefox) just for these type of online transactions so that deleting cookies isn't a problem as it only affects that browser and these sites.

[neiltingley]

I'm flabbergasted. Let me try and few experiments. Firefox in anonymous browsing mood should do the trick.

[Frances_iom]

it's well known especially in the States (well documented on several sites eg Slashdot) - also occurs with some airlines + possibly ticket booking sites - one documented system was that if you looked up prices (esp cut price offers) but closed the session but then came back to book, the price quoted would be higher on assumption that since you had returned you hadn't found a cheaper price but were obviously going to purchase - clearing the cookie meant you saw the original lower price on any return visit.

Personally I allow very few cookies + block most - I totally block in the host file any access to google analytics etc - however you may also wish to clear all history and browse whereever possible with Javascript turned off - another typical tracking dodge is to trace the images (often just a single invisible pel) accessed by a page load - if your visit accesses the image then likely to be a new visit - if the image is not loaded because it is in your cache then site knws you have been before within lifetime of image.
If however you are stupid enough to have javascript + flash enabled then total ownership of your browser history is readily available to anyone

[Resurrection Man]

Neiltingley....yes that should work.

Frances_iom....that wasa good tip re images! Devious so-and-so's.

EDIT: Original link in OP removed as research suggests it is 90% an urban myth.

[Nick Armstrong]

There has recently been bit about this in the media. There are suggestions that some sites charge more when they detect that you are using an Apple Mac (because they assume that if you have an Apple Mac then you must be loaded!).

Alarmed mac user here!!

Look forward to further comment on this!!

[OldTechie]

It is not the cookies that tell the far end what you are using - it is the user agent details in the header of the network request. So private browsing, clearing cookies etc does not fix it. The data is sent from your browser to tell the web site how to format the returned page. It's a nightmare for web developers, they have to send different data depending on which version of which browser you use and which operating system it is on in order to get the same effect on screen.

Safari on my Windows 7 sends:

Default:
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.57.2 (KHTML, like Gecko) Version/5.1.7 Safari/534.57.2

But I can change it (using the menus) to pretend it is Safari on a Mac:
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.57.2 (KHTML, like Gecko) Version/5.1.6 Safari/534.57.2

Or I can select IE9, and Safari will send:
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0;

IE9 on Windows 7:

Default:
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)

But if I use IE9's menus to tell it to pretend it is Google Chrome it will send
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.99 Safari/533.4

Chrome on Windows 7:

Default:
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11

But I can set Chrome to pretend it is a Blackberry:
Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en-US) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.0.0.187 Mobile Safari/534.11+

Or I could set Chrome to pretend it is Firefox on a Mac:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:7.0.1) Gecko/20100101 Firefox/7.0.1

Firefox 16.0.2 on Windows 7:

Default:
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20100101

This "user-agent" string can be set on all the above browsers from menus (if you can find them) except on Firefox. They all reckon it is a bad idea, so it will reset when you start the browser again.

To change it in Firefox you have to type "about:config" into the address bar then (after ignoring the "Here be dragons!" warning) create a new string value called "general.useragent.override" in the massive list of settings and type in whatever user-agent string you like. Not recommended (especially as it will stay with your home-made string until you manually delete it.)

You can also switch Opera to pretend it is Firefox or IE if you can work out how to get the drop-down selector into the top browser bar.

Generally it is a bad thing to do because many web pages will display incorrectly. So hiding the fact that you are on a Mac is not easy.

[Frances_iom]

It is not the cookies that tell the far end what you are using - it is the user agent details in the header of the network request. ... It's a nightmare for web developers, they have to send different data depending on which version of which browser you use and which operating system it is on in order to get the same effect on screen.

and this goes totally against the idea of HTML which is to allow the user to format a page as they desire - if this had been accepted by advertisers' life would have been much easier - however in older Firefox there were several addons that allow easy change - eg when Google started to be awkward I switched to 'Guess' which removed some of their unwanted 'formatting'

[neiltingley]

I tried some searches with Expedia and booking.com and the offers were identical on two browsers, one anonymous the other my usual one. Hmm.

[neiltingley]

Oh its user-agent. Some browsers can spoof it. Let me try a few more experiments.

@Frances-iom - headers are defined in the HTTP protocol.

[Frances_iom]

Oh its user-agent. Some browsers can spoof it. Let me try a few more experiments.

@Frances-iom - headers are defined in the HTTP protocol.

yes but they don't have to be true as several addons can spoof them - spoofing referrer is often a good idea for some sites - I suspect many of the sites that used this trick of an additional Mac-tax no longer do so once it became well known in some circles
Much easier dodges are to own a ticket issueing site and a ticket touting (aka as returns ?) site - if sales look too good (eg for pop/sports events) move more to the touting site and charge inflated prices - I'm sure you can find suitable pairs of such sites owned by the same company but as we all know web based companies are as honest as the day and would never dream of such tricks.
Other dodges are to run synchronised bot nets to give an unfair advantage in entry to waiting rooms etc for booking system - eg one such was described in a recent Linux mag which dominated car auctions

[Word]

There has recently been bit about this in the media. There are suggestions that some sites charge more when they detect that you are using an Apple Mac (because they assume that if you have an Apple Mac then you must be loaded!).

I believe this refers to hotel bookings through 'Orbitz', as reported in The Wall Street Journal, where they justify presenting Mac users with offers for more expensive rooms on the basis that they tend to book more expensive rooms. (We'll give them the benefit of the doubt and assume that their sample data predates the introduction of the practice.)

It's a fairly crude example of the tracking, profiling and targeting that Google and other on-line advertising networks undertake so probably not that surprising. As long as they don't start charging different prices for the same item they avoid most allegations of illegality but it is interesting to consider just how different two people's views of a given set of websites may be.

[Dave2002]

Other dodges are to run synchronised bot nets to give an unfair advantage in entry to waiting rooms etc for booking system - eg one such was described in a recent Linux mag which dominated car auctions

You seem to know a lot about dodges. I don't fully understand the auction/waiting room one - can you give more details, or tell us which mag described it? Re the touting site suggestion, do many organisations actually do that in your opinion?

[Frances_iom]

since it has a cover marked 'Build a Botnet' - should be obvious but try Dec 2012 Linux Mag
re ticketing - I've seen serious suggestions that this is so for big pop concerts where norminal £50 or so seats were going for 10x that
re dodges with cookies so 2nd visit gives a more expensive seat - yes a certain ferry company once tried that (and if others are to believed also a certain cheap airline) - again based on comments from a web forum giving suggestions to clear cookies before 2nd visit