Introduction: there is something that has not been mentioned

The news dates 13 June 2012, two weeks ago: online retailer imposes a tax to users purchasing online with IE7.
I waited on purpose before commenting it, but I feel there still is an important aspect which has not been covered, and can be summarized by this blog title and subtitle. What follows is an in-depth explanation of the reasons.

 IE7 tax warning on 

The retailer message starts a little too rude in my opinion:

“It appears you or your system administrator has been in a coma for over 5 years and you are still using IE7.”

What I think Mr. Kogan really wanted, was to shock and make some hype, and he succeeded: the news was blogged and retweeted hundreds of time, and covered by major news sites.

What surprised me most was that, while the tax raised many approvals and critics, among the latter the concerns were mainly focused to point out how unskilled their web developers are not being able to support IE7 for an e-commerce site.
True enough, supporting IE7 is not such a great deal, especially with the large availability of CSS and Javascript frameworks, but what many seem to miss is:
today one cannot afford ignoring IE7, even if its market share is negligible.

Why? Because since IE8+, Microsoft browsers support the so called “compatibility mode”, a way to switch the browser rendering engine to make it render web pages as IE7 does.
“(IE7) compatibility mode” stems from a time when IE7 was the absolute dominator of web browser market, and the new version of the product were about to introduce significant differences in the way it rendered contents, to better comply with the official W3 specifications.

Once IE7 compatibility mode is triggered for a site, be it by accident, because of an explicit directive in the html, or because the browser decided on its own to switch rendering engine (!), it has the bad habit to keep switched on without the user even realizing it.
It is quite common to have IE9 rendering as IE7. The bad news is that while IE7 amounts to a little more than 1% of the browser share in Australia, IE is by large still the market dominator there, with IE8 and IE9 summing up to nearly 40%.

 On July 2012 in Australia the market share of IE7 is about 1.3% only (courtesy of 

A “compatibility mode” switched IE8+ browser presents itself as IE7, thus the percentage of users potentially driven out from purchasing can sum up to 40%

 On July 2012 in Australia the market share of IE browsers which can switch to IE7 compatiblity mode sums up to 40% (courtesy of 

Demonstration: how IE7 compatibility mode can trigger the IE7 tax

I'm now going to show how a modern IE9 browser behaves in web site during an online purchase attempt, having compatibility mode first turned off and then turned on.

Kogan’s site on IE9, with IE7 compatibility mode turned OFF: site on IE9 with IE7 compatibility mode off

IE9 developers toolbar shows the Browser mode as IE9:

IE9 developer toolbar with document mode as IE9

Sniffing the HTTP request with Fiddler we can see the used user-agent string:

IE9 user agent seen with Fiddler

The user agent string is:

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

Now, still using IE9, let’s switch IE7 compatibility mode ON: site seen with IE9 and IE7 compatibility view switched on


The user-agent clearly states IE7, and that is what most web sites would think the browser is:

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; MDDR; InfoPath.2; .NET4.0C; .NET4.0E; OfficeLiveConnector.1.5; OfficeLivePatch.1.3)

Let’s try to make a purchase

Warning, prepare to some pain: Despite the claim to have spent a lot of effort to render correctly with IE7 (and the use of conditional css comments in the page html seem to confirm it), the user experience is terrible!

Et voilà! The IE7 Tax notice appears in IE9:

IE7 tax warning showing up in IE9

As we said, the potentially affected browser are 40% of the Australian market share (but really, users would bounce away well before trying a purchase, being the user experience so painful!).

An easy FIX

Even if the browser claims to be IE7, it’s not hard to spot a clue to what it really might be.
Let’s have a second look at the user agent string:

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; MDDR; InfoPath.2; .NET4.0C; .NET4.0E; OfficeLiveConnector.1.5; OfficeLivePatch.1.3)

Windows NT 6.1 stands for Windows 7, which never shipped with IE7; WOW64 suggests a MS x64 OS, and it too never shipped with IE7.
At least web developers could have made some attempts to reduce false positives.

Detail of 'avoid the IE7 tax' section on transpire most, is a bias against not IE7 in particular, but against MS IE in general: no indication is given to upgrade from IE7, and the links and icons in the “Avoid the tax, use a better browser” section do not list IE.

Even more fun:
If you try spoofing the user agent as IE6, the notice does not appear! This makes you understand how poorly they bothered to implement the feature.

Did Kogan hurt its own business?

Probably not:
He might have lost some customers, as the technical execution of the marketing “IE7 tax” was poorly performed, but at the same time he gained a great back link profile for free (mistakes apart).
Mind you: all the new visitors he acquired are hardly targeted prospects: MS haters, SEO observers, tired web developers, curious lurkers, the large majority of them not based in Australia.
What makes the stunt a winning one is that the new backlinks are often from high PR web sites, and diversified or branded anchor-text; in a time of Penguin Updates it’s not bad at all!
He might have lost some profit in the short run, mainly due to the poor execution, but will very soon harvest the benefits of the strong backlink profile.

Kogan transformed a badly designed (under the cross-compatibility aspect) web site into an opportunity to build links.
I expect the site layout to be updated soon with greater X-browser support, as it already seem to be in the counterpart.

Is it wise to follow the trend and apply an “IE7 tax” on your own site?

I really don’t think so!
It worked for Kogan because he was the first to do it, and the marketing stunt resonated as desired, but anyone else copying the tactic would be a “me too”, without attracting any press coverage with a stale tactic which, if badly applied, could negatively affect the conversion rate of 40% of your visits!
If I were a competitor, I would instead ride the tail of the hype, but in the opposite direction, sporting an "IE Tax Free" logo.


  • Cutting out IE7 today you might cut out a much, much greater slice of your potential customers, and you cannot afford it.
  • Freely available CSS and javascript frameworks make x-browser support easier than ever
  • Kogan’s trick would not work again for you, you’ve better squeeze your creativity with something new

And you, what percentage of potential customers are YOU currently cutting out?