WordPress has had a Turbo feature for a while now. The feature uses Google Gears to store many of the Admin Dashboard resources (images, CSS, etc.) locally on the client machine. This improves overall performance and responsiveness of WordPress.
If you read the technical details on how Gears is being used, you’ll see that no fancy SQL or Worker Threads are needed to make this work. Only the offline cache is needed. Firefox 3.1 is shipping with the necessary HTML5 Application Cache support to implement the same feature natively – no Gears plugin needed.
In fact, a native approach means the “Turbo” link isn’t even needed – it just works. Better yet, the long list of instructions for downloading and installing Gears is completely avoided.
It. Just. Works.
Hopefully, the WordPress bug to add support for HTML5 Application Cache lands soon.