I got a gloating email today from those awfully clever folk at Wolfram Alpha which informed me that the iPhone app version of the 'Computational Knowledge Engine' popped up on the App Store What's Hot list. What's more, they positively gushed at how they were "pleasantly surprised" to see the app "appear on the store's 'Top Grossing' list on the second day it was available and remain there through the week".

Perhaps whoever wrote that email should have first asked the Wolfram Alpha engine why the app was on the top grossing list. I suspect that drawing on more than 20 years of development, 50,000 plus built-in algorithms and 10 trillion pieces of continually updated and curated data, it might have popped out the following answer: because it costs fifty bucks, stupid.

Sure, it may well let you get "expert-level answers to your specific freeform questions—complete with stunning, dynamically generated visualizations and tables, and richer and deeper information than you imagined possible" right there on your iPhone. It may well come replete with "elegant native iPhone interface that includes a special notation keyboard, customized iPhone output, editable history, and integration with maps and other iPhone services" for good measure.

It may well also be less than half the price of a graphing calculator at $49.99 as one Wolfram Alpha spokesperson has insisted, while missing the point that an iPhone graphing calculator app can be picked up for just a couple of bucks. And missing the point that a graphing calculator doesn't need an Internet connection to work. And missing the biggest point of all, that anyone with an Internet connection (including iPhone users) can use the full Wolfram Alpha service on the web for a lot less than $49.99 - to be precise, for £49.99 less as the service is totally free.

Which makes me sit back and ask myself just who is buying this app on the iPhone in such volume as to push it onto those top grossing and what's hot lists? Now I don't claim to be the brainiest of boxes, but I'm not stupid enough to be paying $50 for something that I can get for free.