The increasing fragmentation of Firefox

About half a year ago Firefox 4 was released and with it a new approach from Mozilla, a fast release cycle modeled after the rival browser from Google. Unfortunately, the effects haven’t been all that positive: the market share of Firefox is continuing to shrink and on top of that the rapid release model has been criticized by companies for not giving them time to fully test against internal applications.

Another problem becomes apparent if you look at the breakdown of browser market share for the past months: Firefox is becoming more and more fragmented between the individual versions! Before version 4 launched, most of Firefox users (about 85% of them, according to the data from StatCounter) were running the latest version, 3.6 at the time. Afterwards the percentage started shrinking, as more and more users choose to stick with an older, unsupported version; it generally hovers around 50% and even drops below around the time of new releases. Chrome on the other hand has kept a very steady pace on this indicator, between 88 and 92%. Right now, there are 4 major Firefox versions with more that 1% market share, something you can only see by Internet Explorer.

Another thing that I noticed looking at the data is that each new version reaches a smaller peak in terms of market share relative to the previous: compared to Firefox 3.6, which had around 25% share at the beginning of the year, Firefox 4 only reached 16.3% in Week 24; Firefox 5 and 6 both peaked around 15.2%. That is to be expected, considering the overall shrinking market share of Firefox, but it’s also a sign that users are not updating fast enough to completely obsolete older versions. This has unpleasant consequences not only for web developers, who need to test their sites in more and more browsers (as if Internet Explorer wasn’t enough!), but also for the end-users, who end up running browsers with known security vulnerabilities; even a couple percent of worldwide browsing translates into millions of people.

Basically, Firefox is caught between two alternative models of backwards compatibility: the Chrome approach – to update so quickly that at any point in time most users will run the latest version and there will be little need for backward compatibility; and the old Internet Explorer model, in which each version is tied to the OS and gets extended support, even years after a better version is out. Before Chrome launched, all the browsers used the slow update cycle and Firefox was no exception. Now that Google delivered a different and much more efficient model, Firefox is trying to adopt it, but unfortunately the old-era legacy is hard to shake off: on one hand the extension ecosystem needs a massive overhaul to keep up with the fast release cycle, otherwise users will stay behind, waiting for the extensions to become compatible; on the other hand companies deploying Firefox complain they can’t test new versions fast enough. Granted, Mozilla is working to solve both of these issues, but until they get practical solutions the market share will continue to fragment more and more with each new version. A technical solution has always been present, hidden in a Firefox config entry, but enabling it by default isn’t a good idea until add-on compatibility from one version to the next is assured.

As I final (troublesome) observation, let’s look at the browser market share in Germany, a traditional stronghold for Firefox. Here the association with Google and the perceived privacy issues have stopped Chrome’s adoption at about 10% market share, but Firefox is still losing ground, even faster than worldwide: from more than 60% at the beginning of the year, Firefox is currently used by only about 51% of German Internet users. Virtually all those users have migrated to Internet Explorer, specifically to IE9, who is now closing in on 10% share, probably soon surpassing both Chrome and Firefox 3.6. An interesting trend…

All the data comes from StatCounter and you can view it online in this Google Docs spreadsheet.