If you ever lose power or your Internet service is temporarily down, you'll no longer be unable to sift through your old e-mails. The catch, though, is you need to use Google's Web browser, Chrome, to access the feature. It's available as an app from the Chrome Web Store.
Titled Offline Google Gmail, the app works by constantly synchronizing the user's Gmail account and keeping locally stored versions of e-mails as they're received.
Then, if you find yourself with no Internet access but still need to pull up an e-mail - say, a hotel confirmation when you get to the front desk, or contact information for your cable company when service goes down, or anything like that - you can open the app and easily find what you're looking for.
The presentation is more like Microsoft Outlook than the standard Gmail aesthetic, which may point to Google's increasing pressure on its giant software rival.
To that end, Google is also beginning to roll out offline versions of Google Docs, which will be a much more direct threat against Microsoft Office since it will essentially act as a free suite of office software instead of a cloud-based online-only tool.
Google previously tinkered with the idea of offline Internet access, allowing users to create cached versions of every website they visited, and then if they ever tried to go to those sites without an online connection, instead of displaying an error message it would pull up the most recent cached version.
The project was called Google Gears but it never really took off. Perhaps it was a bit ahead of its time. Nevertheless, bringing Gmail and Google Docs to users anytime, anywhere is certainly a very helpful feature.