Gears API Blog:
If you’ve wondered why there haven’t been many Gears releases or posts on the Gears blog lately, it’s because we’ve shifted our effort towards bringing all of the Gears capabilities into web standards like HTML5. […] We will not be investing resources in active development of new features. Likewise, there are some platforms that would require a significant engineering effort to support due to large architectural changes.
Gears will not be supported in Safari for Snow Leopard or later, and they currently plan to support Firefox and Internet Explorer moving forward.
I was really excited about Google Gears when it was first announced back in 2007. But, it’s a different world now, HTML5 is the future and I’m glad the folks at Google are smart enough to admit it. I don’t expect Gears to stick around for too much longer.