I agree with PPK on one count.
The return on your investment in time and resources when your build a mobile site will always pay back the most dividends if you just go ahead and target the majority of your audience’s mobile clients.
More often than not, though, and even more so if your site’s readership is primarily US-based, you would be doing yourself a disservice by not targeting the mobile Webkit found on the iPhone, iPod touch, Android, and WebOS.
His sales stats might be technically correct in saying that the Nokia/S60 browser is the most widely installed mobile browser in the world, but it means exactly jack shit if no one is using it to browser the web (they aren’t in the US, apparently).
Go to any major website and survey the mobile clients in use and you will find the vast majority are iPhones and iPod Touches; a growing percentage will be Android and WebOS.
SymbianOS will be somewhere down around 1 or 2 percent.
In fact they are quite savvy and well aware of where they should be focusing their efforts, energy, and money. Perhaps this can be shortsighted at times (see: IE6 c. 2000), but I can’t exactly fault anyone for pursuing those choices for those reasons at that time.
We aren’t looking at our web stats, seeing a million Nokia S60 users and 10,000 iPhone users and barreling ahead an building an iPhone compatible mobile site.
Webkit, and specifically iPhones and iPod touches were by and far the most popular platform with Android, WebOS, Blackberry, and Windows Mobile coming next.
Now, you tell me how you justify to your bosses that you should be spending your time and your company’s money on targeting a browser based off PPK’s stats when, for most people, they have no basis in reality.