Imagine this scenario: Overnight someone sneaked into my office and upgraded an application on my computer. An application I had been running happily for months, and one that worked well and served my needs.

Obviously, nobody asked me if I wanted the upgrade. What’s more, the phantom upgrader also didn’t check that the new version was compatible with my Mac. Okay, maybe they did test but decided that the wrinkles weren’t all that bad and that I could probably live with them until they got around to sneaking back in again and doing another drive-by upgrade.

Sounds absurd, doesn’t it? Absurd, yet that’s exactly what happened to me a couple of weeks ago. I was preparing for a trip to San Francisco and mapping all kinds of things - my hotel, the conference venue, my friends’ houses and the place I’m going to show off my awesome born-in-the-UK bowling skills. Then Google decided to roll out a new version of Google Maps and it didn’t work cleanly with Safari.

Here I am, in the middle of an important organisational project and the single most important application for that project was just given a disruptive upgrade. Did anyone warn me that I should expect and plan for disruption? No. Could I pull out the installer CD and go back to an old, known-good version of Google Maps? No. Could I long-term refuse to upgrade on the basis that the current version met my needs and I prized stability over features? Not a chance.

Now, I don’t intend this to pick on Google Maps. It’s a product I love and use all the time and I’m as delighted as the next person when I go to my favourite web apps and great new feature have just appeared. I jumped for joy when I discovered that Google Maps had added satellite images for the UK. I was delighted when Flickr added image clustering, but what’s clear is this:

Web 2.0 applications are not just websites anymore - they’re applications (and, in some cases, platforms) that people have begun to critically depend on for their work.

I don’t personally use 37Signals’ Backpack application, but I hear a lot of raves about it in the productivity circles I hang out in. What happens when your central productivity application and all its data is no longer under your control? What happens when it’s down for maintenance? Is this an acceptable business risk? I’m a firm believer in outsourcing those business needs outside one’s core competency, but I’m a bit of a sceptic here.

Of course, there are many matters that are far from business-critical for which it will make perfect sense to hand off responsibility to a web-based application host. Flickr is a great example - I can live for a couple of hours downtime where I can’t post my photos. My Livejournal is another fine example. Even downtime on my IMAP mail server is mostly bearable, on account of having a rich local cache which ensures continuity of access to existing information. The subject of the “rich local cache” is a whole other topic for another blog post.

My point is simply this: until you can use web applications offline, their appeal and broad application is necessarily limited to those times and locations where bandwidth is readily and reliably available.

Been hit with a flaky upgrade? Love the ease? Hate the surprises? Talk about it.