"It looked like the next battleground for the web," noted Nightingale. Now he says, "we've been watching Metro's adoption. From what we can see, it's pretty flat."
While pre-release versions of Firefox's desktop browser are beta tested by millions of people, the company never saw more than 1,000 active daily users taking advantage of Metro.
If a bug exists in a Metro app, does anyone hear it?
The problem with Microsoft's new design language isn't just that it's unpopular; it's also hard for app developers to properly bug test their software.
Nightingale theorized that Mozilla could have eventually shipped the Firefox Metro app, but without real-world testing, a lot of glitches would have been discovered by end users.
Instead, Mozilla will focus on its development efforts on existing Firefox platforms, including Mac, Linux, Android and straight-up Windows.
Maybe when Windows 9 rolls around, it can consider giving Metro another go, but for now it says the real costs of investment in a platform its users have shown little sign of adopting isn't worth it.
- Firefox is still available on Androids like the Samsung Galaxy Note 3
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