"A gear is a component within a transmission device that transmits rotational force to another gear or device." (Wikipedia)
Most people think that Google Gears is a way to make web applications work offline, but it's much more than. Google Gears addresses many limitations from today's browsers and wants to make the browsers more powerful.
Here's a list of features that could be included in the next releases, but you can find more in Google Gears wiki:
* image manipulation - "a module to give Javascript a way to resize, crop and compose images together on the client side. This will allow, for example, images to be resized into a web-friendly format before being uploaded to a photo album. Another use is for composition of images together as an efficient alternative to server-side composition or CSS layering. Yet another use is for basic photo editing - a user can edit a photo with instantly applied changes before uploading it to the server."
* location - "an abstraction for the various LBS APIs that currently exist on mobile platforms (GPS-based, network/cellid-based). The API consists of the Location class, which encapsulates various location attributes (latitude, longitude, etc), and also provides the means to query the platform for a location fix." This suggests that Google Gears will be available for some mobile phones.
* desktop shortcuts for web applications that lets you click on an icon from your desktop and open the "application" in your browser. This could make the transition from the desktop to the browser easier, even if some people could find it confusing. Mozilla Prism is a similar initiative.
Google's Dion Almaer describes Gears in a very plastic way. "We get to drive a few makes of cars (browsers) on the (information) highway. When we want new features, we have to wait for a new model to come out, and recently it feels like Cuba. The top selling car is a 1950’s Chevy. As drivers that are passionate about the driving experience, the Gears team is trying give everyone a foundation to replace the engine, even as you drive."
Google Gears is still in an early phase of development and it could include many other features, but it will be interesting to see how Google intends to push its adoption. The Gears-enabled services could ask the users if they want offline access or other fancy features, Google could also include it in the toolbar or distribute it with popular applications from third-parties. For now, Google Reader, Remember the Milk and Zoho Writer are the most important applications that use Gears, but next year most Google services will use Gears.