Google will begin to offer browser-based offline access to its Gmail Webmail application, a much-awaited feature.
This functionality, which will allow people to use the Gmail interface when disconnected from the Internet, has been expected since mid-2007.
That's when Google introduced Gears, a browser plug-in designed to provide offline access to Web-hosted applications like Gmail.
Gears is currently used for offline access to several Web applications from Google, like the Reader RSS manager and the Docs word processor, and from other providers like Zoho, which uses it for offline access to its e-mail and word processing browser-based applications.
Rajen Sheth, senior product manager for Google Apps, said that applying Gears to Gmail has been a very complex task, primarily because of the high volume of messages accounts can store. "Gmail was a tough hurdle," he said.
Google ruled out the option of letting users replicate their entire Gmail inboxes to their PCs, which in many cases would translate into gigabytes of data flowing to people's hard drives. It instead developed algorithms that will automatically determine which messages should be downloaded to PCs, taking into consideration a variety of factors that reflect their level of importance to the user, he said. At this point, end-users will not be able to tweak these settings manually.
"We had to make it such that we're managing a sizable amount of information offline and doing it well in a way that's seamless to the end-user," he said.
For example, in Gmail, users can put labels on messages, as well as tag them with stars to indicate their importance, and Google can use that information to determine which messages to download. Sheth estimates that in most cases Gmail will download several thousand messages, preferring those that are more recent as well. Depending on the amount of messages users have on their accounts, they may get downloads going back two months or two years, he said.
Google will begin to roll out the Gmail offline functionality Tuesday evening and expects to make it available to everybody in a few days, whether they use Gmail in its standalone version or as part of the Apps collaboration and communication suite for organizations.
While the feature was "rigorously" tested internally at Google, it is a first, early release upon which Google expects to iterate and improve on. That's why it's being released under the Google Labs label. Users are encouraged to offer Google feedback.
Users have been able to manage their Gmail accounts offline via other methods for years, since Gmail supports the POP and IMAP protocols that let people download and send out messages using desktop e-mail software like Microsoft Outlook and others.
However, the Gears implementation will let people work within the Gmail interface without the need for a separate PC application. When offline, messages will be put in a Gears browser queue, and the desktop and online versions of the accounts will be synchronized automatically when users connect to the Internet again. This will come in handy for people who travel a lot and often find themselves without Internet access, Sheth said.
To activate the offline functionality, users of standalone Gmail service and the standard Apps edition should click "settings" after logging on to their Gmail account. There, they should click on the "Labs" tab, select "Enable" next to "Offline Gmail" and click "Save Changes." A new "Offline" link will then appear in the right-hand corner of the account interface. Users of the Education and Premier Apps versions will have to wait for their Apps administrators to enable Gmail Labs for everyone on the domain first.
Google is also rolling out Gears-based offline access for its Calendar application. However, it will be for now read-only and exclusively available to Google Apps account holders. Previously, Google introduced read-only offline access to the Spreadsheet and Presentation applications in Google Docs, which is also part of Google Apps.