Until April 2005, some applications provided a dictionary, but each had its own. Then Mac OS 10.4 Tiger was introduced and included a system-wide dictionary: teach it the word “Hisham” in Mail, for example, and all the other Mac programs now knew that Hisham is not a mistake (though some friends might disagree!)
I thought that Firefox was the only Mac app to still provide its own dictionary instead of taking advantage of the Mac’s built-in one, but I found a worse app this week: it neither uses the built-in one nor provides its own. The developers suggest that you “Take the time to copy edit your work so that you can avoid embarrassing typos…”:

In essence, you need to type your text in another app, then copy and paste it. And not just to have your work spell-checked: this app’s edit field is not resizable — a very un-Mac experience. You don’t have to type long before it becomes a chore.
Yes, you probably realized it by now: the guilty app is Apple’s own iTunes. iTunes has always had two faces. The nice, Mac-like one is fast and feels, well, like a Mac. The bad face is the iTunes store part of the program that’s built using WebKit. But this hardly excuses iTunes: Safari too uses WebKit but feels a lot zippier, and yes, supports the built-in dictionary.

