John Lilly, Mozilla’s Chief Operating Officer, has estimated that Firefox, the company’s popular open source web browser, is used by at least 126 million people around the world.
Firefox’s penetration into the market is a popular topic among technology enthusiasts, but most market share reports don’t paint a clear picture. Many of these reports are done by collecting statistics from a wide selection of sites, but Lilly points out
that the results can be skewed depending on the types of sites being used for the data sample.
“The most basic issue is that there’s no way to really represent the complexity and the dynamism of the global Web — it’s just too big, with too many things changing too rapidly,” he explained.
With sites that are focused on early adopters and technology enthusiasts, like bit-tech
for instance, Firefox’s market share will be higher than it is on publications that have a broader mass market appeal. Lilly was quick to ensure people didn’t understand the point he was making though.
“Don’t misunderstand: all of these studies are extremely useful and help understand what’s happening around the world,” he said. “I’m just asserting that it’s very important to understand the limits of particular studies and the assumptions that are baked in.”
Lilly arrived at this number by leveraging the data collected by the Firefox Application Update Service, whereby the browser sends an anonymous request to the update servers each day to check for updates.
By counting the total number of pingbacks, Mozilla is able to estimate how many instances of its browser are running on a given day. This is a number it refers as the Active Daily Users (ADU). Back in October 2006, there were around 23 million ADUs and in November this year, the number of ADUs peaked at almost 49 million – more than doubling in size in just over a year.
So how did Lilly get to 126 million from the 49 million peak ADUs? Well, his maths gets a little creative at this point, as he multiplied the ADU number by three.
Yeah, we told you it was a little creative... but he makes a fair assumption that not every Firefox user is using Firefox every day of the week and there’s also the fact that corporate firewalls and proxies could also be preventing large numbers of Firefox installs from communicating with the update servers.
That said, Lilly believes that the estimate is a conservative one, saying that “this is a conservative multiplier (we think it could be more like 3.5) that we’ve gotten to by doing some of our own experiments, piecing together data we’ve received from sites who have done their own calculations, and then really testing them against the best common sense top-down tests we can.”
With an estimated 125m monthly unique users, Firefox’s market share would represent just 10.5 percent of the total number of Internet users around the world (which is reported to be around 1.2 billion per month). This is appreciably less than where most reports suggest Firefox’s market share lies, which explains why Lilly believes that the estimate is on the conservative side.
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