The chief executive of Opera Software claimed on Monday that the market share figures for Mozilla Firefox are inflated, due to its support for link prefetching.
Link prefetching is a mechanism that uses browser idle time to download Web pages that the user might visit in the near future. This feature is enabled by default in Firefox 1.0. Google added support for link prefetching to its search engine earlier this year, which means that Firefox will pre-load the top search results into its cache.
Firefox and Opera have a market share of 8.7 and 1.0 percent respectively, according to the latest figures from Web traffic measurement company OneStat.com. Microsoft's Internet Explorer is still the dominant browser, accounting for 86.6 percent of Web surfers. But Jon von Tetzchner, the chief executive of Opera, claimed that Opera's market share is likely to be higher than these statistics suggest, as it does not support pre-fetching and has a more efficient caching mechanism.
"Sadly the statistics are undercounting Opera and overcounting Firefox. Opera has a better caching mechanism so it doesn't access Web sites as often as other browsers. Firefox has added a pre-loading feature that Google has made use of. This inflates the numbers on the statistics," von Tetzchner said, in an interview with ZDNet UK on Monday.
Opera's caching mechanism is not the only feature that could deflate its marketshare. Opera is configured by default to identify itself as Internet Explorer, a setting that users have to manually change to allow Opera to identify itself correctly.
There are between 10 and 15 million active users of Opera, according to von Tetzchner. He said that Opera is being downloaded between two and three million times per month. Opera also produces a version of its browser for mobile phones, which has been downloaded over one million times and "many millions" of licences for this browser have been sold to handset manufacturers and operators, according to the Opera Web site.
James Governor, an analyst at RedMonk, agreed that market share figures can be inaccurate, but said download figures can also be unreliable.
"When they're looking at downloads, they're not counting who uses the thing — I have Opera on my desktop that I don't use. For all that Opera is supposedly being used on mobile phones, do people actually use it?" queried Governer, adding that "you have to be careful about throwing stones."
Although a free version of Opera is available, this version has advertising built-in, while a paid version without advertising is also available. Von Tetzchner admitted that the adverts put off some users, but as his firm does not have independent funding it has little choice.
"A lot of people don't like our ads, which is sad as we don't have a rich sugar daddy like the Mozilla Foundation. They [the Mozilla Firefox team] don't have to think about money as they're being funded. We're not being funded," said von Tetzchner.