It's one of the most persistent images of the future that we already have today. Wireless broadband has liberated us from the tyranny of the office or the chaos of a kid-riddled home. We can work from wherever we like — although, for some reason, it's almost always by a swimming pool or white-sand beach. We can run the household from wherever we like, too — although, for some other reason, it's almost always at a coffee shop in a suburban shopping mall.
The wording of Telstra's promotional material is typical of the genre. "Whether you're on a train, in a cafe, or on your beach holiday, you can connect to the world around you, download and stream your favourite content, and access your emails without any hassles when you're out and about in Telstra coverage areas," says the website, and the plans have names like "Freedom" and "Liberty".
But if you actually try to live this life of liberty, as I've done recently, you'll soon find that the freedom is illusory — at least here in Australia, and at least if your online life is anything other than peasant-grade.
It's the same kind of freedom you can expect on prison day-release. You can wander a little bit, but you'll have to be back on your fixed-broadband leash by nightfall.
The key problem is the minuscule data transfer allowances. There's simply not enough to sustain a reasonable day's online activity.
Until a few months ago, the most data that Telstra would provision onto a mobile broadband service was 15GB per month, and both uploads and downloads counting towards that quota. Optus offers a 20GB plan. Vodafone tops out at 5GB per month, although there's the option to add extra data at $20 per gigabyte.
Using 15GB per month as an example, if for no other reason than that's the plan I'm on, it gives you half a gigabyte per day. A mere 500MB. For everything you need to do in an entire 24-hour day.
It doesn't go far.
Watching just one hour of streaming video, such as ZDNet'sfrom Monday this week, will blow at least half of it. YouTube videos can vary wildly in bandwidth requirements, but ABC TV says the streaming version of their News24 channel is 300MB/hour in high resolution, or 200MB/hour in medium resolution.
An audio-only conference call on Skype burns around 50MB/hour each way, so that's 100MB/hour off your quota. Add video and ... well, forget it. There are reports of Skype video calls burning 500MB of data in just 45 minutes.
But even without the supposed luxury of video — and I contend that in 2013, video isn't really a luxury, or shouldn't be — what I've learned this month is that when you "connect to the world around you" with your laptop and mobile broadband link, all the little pieces add up fast.
Want to stay in touch with the news? ZDNet's home page weighs in at 1.8MB. The Sydney Morning Herald's is 2.2MB. News.com.au's is 2MB. Check the top 10 stories at each of five sites, and there goes 100MB.
And then there's the cloud.
Every single one of those services we expect to be connected to 24/7 contributes its own steady trickle of data. "If you are signed in to Skype, but not making any calls, Skype will use, on average, 0-4kbps," warns a Skype support page. Add in constant anti-virus updates (or check-with-the-cloud traffic); Evernote notebook synchronisation; cloud storage synchronisation, such as Google Drive or Dropbox; checking email, even if there's no new email to download...
My estimate is that even in my relatively sparse configuration, this background chatter alone constitutes almost 100MB per day.
Then on top of all that, there's the updates to your operating system and all your application software. How big was that last Patch Tuesday download? The last OS X update that also updated iTunes and iPhoto, and all the rest? That probably blew two days' allowance without you accomplishing anything.
Don't even think about BitTorrent.
Now in the telcos' defence, I don't think anyone's claiming that mobile broadband can serve as your sole internet connection — at least, not in any way that'd get them into trouble under consumer law. And like any sensible business, their prices are whatever they reckon they can get away with.
Bigger plans are becoming available. Since 25 November 2012, Telstra has offered a 25GB plan for $160 a month — although, it's not heavily promoted and it's still less than 1GB per day. If you know where to look, they have a business mobile plan with 120GB of included data for (gulp!) $600 a month.
But unless you have that kind of money, a mobile-only existence is certainly not "without any hassles". It is, in fact, one constant hassle. Of monitoring data usage. Of guessing how much data you've used since Telstra's data usage meter updated six hours ago. Of hitting your quota unexpected, and either having to pay those eye-watering data over-run charges or being throttled back to impossible-to-use dial-up speeds.
No, the mobile broadband liberation won't have arrived until we can spend an entire month online using nothing but mobile broadband, at an affordable price, and without having to ration out our data usage. It sounds to me like that's still years away.