I've started wondering just recently why there is no support at all for cost monitoring on our phones? Okay, on S60 phones there are two applications where you can monitor
- how much time you've spent with speaking on the phone,
- how much data you've up/downloaded.

You've spotted that neither tells how much money you'll have to pay at the end of the month, right?

Obviously, one of the main reasons why there is no such an application on your phone is that there is no such application on the market. Neither built in your phone. Is it that simple, huh? Not really. Let's think about it how our application should work:
- it either keeps track of how much time you've spent with speaking (you called someone or someone called you while you're abroad) and also monitors how much data you've exchanged (up/download, SMS, MMS, etc.).
- or connects to your operator's site and download data from there.

Let's examine these two options in more depth:
- Keeping track of everything on client side: it makes sense to do it as most of the required features are already present. I guess, at least as I presume here that the APIs Logs and Connection Manager applications make use of are publicly available. What is missing, though, the information that could be used to figure out the actual costs. Okay, the tariff could be retrieved from various places and eventually could be typed in into our fictitious Cost Monitor application as well, but first users are usually pretty much lazy to do that, second it's not even trivial to find out which rate we should apply when. For example, how do you know what rate to apply when you're abroad? You can't expect that the user will do all these operations as it's pretty much laborious. Even I would not do that. :- Not to mention the fact that even though it's kept track of e.g. how much data you've downloaded, but I doubt that I could figure out which bearer (e.g. 3G, WLAN) I used each time. As usually we use public WLAN service free of charge or pay for it when we're there, I wouldn't like to see those figures in my calculations. And I'm sure that there are other issues as well that we would need to tackle to get a correct end result.

Briefly: it would be pretty much challenging, if not impossible, to write such an application and even if it was possible it would put a big burden on users' shoulders to manage the application.

- On the other hand, if Cost Monitor application was only a thin client that could connect to the operator's site, then we could put all the burden of implementing the calculation logic on operators' shoulders (can you imagine an operator with shoulders?:). Which, in fact, has already been implemented as operators always know it pretty well how much money they can pull out from your pocket. I guess, some of you have already found it out that there is a little problem with this approach. Not implementation-wise, but from strategic point of view. And well, the problem is not only little, but HUGE: operators will never make such a service (e.g. a Web Services API) available publicly. It's simply not in their interest as it might inspire their clients (i.e. us) to have better control over their costs.

Finally, I did not go into details as to the features of our Cost Monitor application. The obvious one would be to give visual representation of the user's costs. A non-obvious, but very useful, one would be to be notified upon reaching/approaching a pre-set limit. I'm sure that everyone can immediately see why this feature would be opposed by operators - whose help we would rely on, btw.

Looking forward to your comments!

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