Truncating the axes is the oldest trick in the book, so the story this chart is telling is not quite as dramatic as the initial visual impression, but that story is still striking and important.

The proportion of internet usage from mobile devices is tiny, less than 3%.  That’s almost certainly an understatement, since the chart measures operating systems, not connection types, so includes mobile devices rather than devices which happen to be mobile, but the absolute numbers are still pretty much insignificant.

The trend is, quite obviously, another matter. The share of internet usage from mobile operating systems has gone up thirteen fold in the last two years, and the slope of the line is robustly upwards. For all we know, the line might hit some natural ceiling in the next few weeks and never break the 3% barrier. That seems remarkably unlikely, though: if absolutely nothing else were happening, the simple pattern of device renewal which characterises phones as opposed to computers, bakes in substantial future growth to come – and in any case there is no reason to suppose that nothing else is happening.

I thought the chart – which I have lifted from a wider analysis of operating system usage data by Ed Bott – was striking enough to be worth a post in its own right. But then it made me think of an exchange on twitter earlier today:

@Directgov: The Guardian’s Consumer App of the Week features the #jobcentreplus #app from @directgov #iPhone #iPodTouch #iPad http://bit.ly/dgov-app

@Marthalanefox: @Directgov how many ppl going into a jcp have an iphone?

@Pubstrat: @Marthalanefox @Directgov Some certainly do – and the app is also available on android. It’s one more way in to accessing the info online.

@DavidCotterill: @pubstrat @marthalanefox @directgov a few months back the figures were 80k job searches a month from iPhone. Small, but growing…

We seem to be back with the question of whether government should be dabbling with minority interest technology at all. I wrote quite a lot about that in two posts last August – Apps for Elephants and More on Apps for Elephants – and I am not going to go over that ground again. But I think this graph and the challenge implied by Martha Lane Fox’s tweet encapsulate one aspect of that debate very neatly. In essence, the question is whether we should pay more attention to the fact that the absolute figure is still very low, or to the fact that it is growing so rapidly?

There is no inherently right answer to that, no simple rule which automatically determines the right answer. I think government should be very cautious about spending time and money developing at the purely experimental end of the scale. But that’s not where the mobile internet is any more, and it seems pretty clear that we have got to the stage where we should pay serious attention to its rate of growth.

And in the meantime, if you are on the move and looking for a job, you can get the Jobcentre Plus app for iphone/pod/pad or in the android market.