It’s not just that the iPhone actually makes the internet pretty usable on a pocket device. That’s certainly a big part of the formula; but for me, the coup de grâce is that, in the UK at least, it comes with a simple, standard unlimited data package.

That means you don’t need to ration your mobile internet usage. You can use the web the same way you use it at home – for looking around, for trying things out, for exploring. For browsing.

Pence per megabyte

Of course, you can do that with any old phone if you want to: but until recently, it’s been a pricey proposition. With my old Orange contract I paid £10 a month – around a quarter of my total bill – for ten megabytes of data transfer. Ten megabytes a month! Just the front page of Slashdot comes to over 500K.

And, naturally, if I ever used more than that, the price went up even further. Since there’s no easy way to tell how much data you’ve actually consumed at any given point – nor to predict how heavy a page will be until it arrives – I kept my mobile internet use to a bare minimum. (The barely-usable interfaces of most smartphones and mobile browsers played a part too.)

To be fair, not all data plans are as poor as mine was. T-Mobile, for example, offers a range of 1GB-per-month tariffs at quite reasonable prices. And Orange was always trying to persuade me to buy into various deals which would give me better value if I regularly used the net at certain times of day (and worse value if I didn’t).

But I’m not going to change providers just to get cheaper mobile internet access, especially not via the same old clunky devices. Nor am I interested in trying to calculate which mobile internet package best matches my highly sporadic usage.

And if I find that sort of thing too tedious to bother with, I’m pretty sure the man in the street will too.

So I think O2 has got it absolutely right by distilling the iPhone into a very simple proposition: “this is the world’s most usable mobile internet device, and you can use it as much as you like for one flat rate.” That’s an easy message to understand, and the price is pretty competitive too. Just what’s needed to coax smartphone skeptics onto the mobile browsing bandwagon.

Sucking up juice in the pub

For my own part, I was certainly excited about being free to browse without worrying about the bill. I pictured myself using Google to settle even the most trivial arguments in seconds. I imagined myself chatting to friends online just to while away long train journeys. Hell, if I ended up in a ropey pub, I could use the web to find a better one while finishing up my pint. And now I have my iPhone, I can indeed do all of these things.

Unfortunately, what I hadn’t realised is that doing so hammers your battery. I learnt that on my first day with the iPhone, which I largely spent trying out online resources: downloading things from the App Store, browsing Facebook as I walked down the street and marvelling at how the built-in YouTube application, coupled with a pretty decent speaker, turns the iPhone into a free video jukebox.

Within a few hours my battery was almost empty.

You can safely skip this digression

Now, I’m pretty old – or so our staff writers tell me – and I’ve had a lot of mobile phones in my time. But I particularly remember my first phone (a Motorola mr20), which I bought twelve years ago, because it had a standby battery life of around ten hours. And that caused a degree of trauma it’s hard to forget.

With such a short battery life, the thing needed charging every single night. If I ever ended up away from home for the night (hey, it happened), or simply forgot to put it on to charge before stumbling into bed (which admittedly happened more often), I’d be left incommunicado the next day.

Indeed, if someone called me in the morning, I’d always try to cut the call short. Otherwise, the strain on my battery could have caused it to expire before the evening. And then, who knows, I might have ended up missing out on the social event of the season.

Eventually, I upgraded to a Nokia 6130, which lasted for a good three or four days between charges, even when I’d been using it to – shock, horror – make phone calls. My phone-related anxieties evaporated. It was like a weight lifting from my shoulders.

iPhone better than phone from 1996

The iPhone 3G’s battery life isn’t stunning, but it’s nowhere near as bad as my old Motorola. It’s too soon to gauge properly, but it looks like it’ll happily stay on standby for at least three days. My alarming first-day experience arose from abnormally intensive use, which I’ll probably never repeat.

But nevertheless, it’s rekindled my long-dormant battery angst. I can indeed now sit on a train and chat with my friends – but will I still have a usable phone by the time I get to my destination? And yes, I can use Google to find a better pub, but will I be able to call my girlfriend to tell her where it is?

And so I find myself opening Safari with just as much trepidation as I used to open the browsers on my previous phones. The iPhone has delivered me from the fear of running up a huge bill, but in its place has come an equal fear of running down my battery.

For sure, overall the iPhone is still a great stride forward. But, alas, I’ve found that stride comes at a cost of… let’s say half a step back.