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ASA Adjudication on Microsoft Ltd

Microsoft Ltd

Microsoft Campus
Thames Valley Park


3 November 2010


Internet (display)


Computers and telecommunications

Number of complaints:



Crispin Porter Bogusky

Complaint Ref:



An Internet ad, for Microsoft, stated " ... Download the most widely used browser for free at ...".


The complainant challenged whether the claim that Internet Explorer 8 was "the most widely used browser" was misleading and could be substantiated.

CAP Code (Edition 11)


Microsoft said the ad formed part of a campaign which ran from May to July 2010.

Microsoft noted the complainant had argued that, according to a market share tracking site (Net Applications), Mozilla Firefox had a greater percentage share of the market than Internet Explorer 8. Microsoft explained that while the Internet Explorer 8 figure quoted by the complainant referred to Internet Explorer 8's share of the market, the Mozilla Firefox figure quoted by the complainant was the mean usage share of all different versions of Firefox, taken from six share monitoring businesses. They said Net Applications data on the market share of different versions of Firefox showed that the version with the greatest market share was Firefox 3.6, at 15.67% in May 2010, 15.99% in June 2010 and 16.15% in July 2010. That was, nevertheless, behind Internet Explorer 8, which had a 25.18% share of the market in May 2010, a 25.84% share in June 2010 and a 26.87% share in July 2010.

Microsoft said, furthermore, one of the information sources provided by the complainant linked to a Browser Version Market Share table dated July 2010, which listed the five most popular web browser versions and their share. The results were 26.87% for Internet Explorer 8, 16.97% for Internet Explorer 6, 16.15% for Mozilla Firefox 3.6, 11.43% for Internet Explorer 7 and 6.48% for Chrome 5.0. Microsoft argued that the information provided by the complainant did, therefore, demonstrate that Internet Explorer 8 was the most widely used browser. They also provided Browser Version Market Share tables for May and June 2010, which both showed that Internet Explorer 8 had a greater market share than any other browser in those months.

Microsoft said another source of information provided by the complainant gave July 2010 statistics, from the investigations of six different independent monitoring businesses, which stated that Internet Explorer in all its different versions was the most widely used web browser, in that it had a greater market share than Firefox, Chrome, Safari and Opera in all their different versions.

Microsoft said if the Net Applications data referred to by the complainant was used to compare the latest version of Internet Explorer with the latest version of Mozilla Firefox, or all versions combined of Internet Explorer with all versions combined of Mozilla Firefox, Internet Explorer was a more widely used browser than Mozilla Firefox in both comparisons. They also pointed out that according to Net Applications data, Internet Explorer was more widely used than any other browser, whether one was referring to all versions of Internet Explorer collectively, or to Internet Explorer 8 specifically. Microsoft believed the scale and methodology of Net Applications data meant that it currently provided the most accurate measure of browser usage share.


Not upheld

The ASA understood that the complainant's argument that Mozilla Firefox had a greater percentage share of the market than Internet Explorer 8 depended on comparing July 2010 Net Applications market share data, for the Internet Explorer 8 version of Internet Explorer, with a median statistical share from various sources for all versions of Firefox, including historical versions. We considered that was not a valid comparison, because the two things being compared were not equal.

We considered that readers were likely to interpret the claim "the most widely used browser" as being specific to Internet Explorer 8, not as referring to all versions of Internet Explorer collectively, and to infer that Internet Explorer 8 was installed on more computers worldwide than any other browser. We considered that Microsoft had provided evidence which demonstrated that that was the case. We therefore concluded that the claim that Internet Explorer 8 was "the most widely used browser" had been substantiated and was unlikely to mislead.

We investigated the ad under CAP Code (Edition 11) clauses 3.1 (Substantiation), 7.1 (Truthfulness) and 19.1 (Other comparisons) but did not find it in breach.


No further action necessary.

Adjudication of the ASA Council (Non-broadcast)

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