How extensively can you search? The biggest reason I use Gmail is that I can find a message I got two years ago in just a few seconds with the right search terms. But depending on just how much gets cached, your search capability could be severely limited.

Will you work the same way in Gmail whether you're offline or online? That's certainly the way Google makes it sound. If so, that'll be a big step forward from other attempts to bring webmail offline. You've long been able to access your Gmail account through a client like. But that doesn't give you all the Gmail functionality like labels. since last summer using Zimbra Desktop. But that also involves using a client on your desktop. For offline access to Windows Live Hotmail, Microsoft suggests using their Mail client software.

Is Gears up to the challenge? Google launched this system for creating offline access to Web apps nearly two years ago. For a long time, the only apps that used it were Google Reader and to do list Remember the Milk -- an indication that developing for and . In fact, bringing Gmail offline was an obvious use of Gears that has taken 21 months to come to fruition.

(Google also says it's readying an offline version of Google Calendar, also presumably using Gears, though the company didn't specifically say that. Offline Calendar will initially be available only for users of Google Apps Standard Edition and there's no firm release date.)

Is Gears ready now? We'll see soon. I'll check back in once I get a chance to play with Gmail offline. And let me know what questions you have. I'll do my best to answer them.