Every Gmail power users should already know that Google released an offline addition to its popular web based mail service on January 27. Here are some of the most important features of the new addition, which is available in the Labs tab in Settings.

In a nutshell, the Gmail Offline service is not a separate program, in the Outlook or Thunderbird manner, but it is rather seamlessly integrated into the browser version of Gmail. This means that there will be no extra programs on your computer, rather than just a cache file that indexes all of your email items, comprising the inbox, outbox and sent items, along with junk and deleted mail.

The cache file will be as large as your emails on Gmail’s server are, so be prepared for quite a hefty file, ranging from 1GB to 5 or 6GB in size.

Mind you, Gmail Offline requires Google Gears, a not so popular platform, as only Chrome has it bundled. After the feature installs, it will download all email items to your computer, which can take some time, depending of the internet connection. After all the information is synchronized between your computer and Google’s server, you are good to go with the new service.

Google Offline will allow you to log in to your Gmail account even if you aren’t connected to the internet. In this case, Gmail will only display the latest synchronized state of your email items. You can still label, star or search for email items and you can even compose new mail in the same manner as if you were online. The composed emails are stored in the outbox folder and will be automatically sent as soon as you connect to the internet.

Overall, Gmail Offline doesn’t bring any new features with itself, but it’s a nice addition to know that you will be able to flawlessly access your account even if you aren’t connected to the internet.