The most immediately visible of Mac OS X's services. "Services" are what appears to be Apple's attempt to revive OpenDoc, except without the Marxist overtones and done in such a way that this time it has a chance in hell of survival. Applications can disassociate bits of themselves and register them as as "services". If the user can in some way make active a bit of data of a class that the service recognizes, the user can allow the service to wrest control of the program's data away from it for a moment to mess with it in odd ways.

AppleSpell, a Text Service that, um, works on text fields, is a system level spell checker! Literally everything in Mac OS X that uses text fields-- your e-mail, your AIM conversations, and the submission forms on your web pages (i.e., the OmniWeb window i am currently typing this node into))-- has the same built-in spellchecker. There are a few special cases (ProjectBuilder's code areas, etc.) which disable text services, but they are rare. You have no idea how much you fall in love with this feature. Suddenly every single application spoils you just as rotten as your best Word Processor, and you don't see why it should ever be otherwise again.

AppleSpell can be invoked in a couple of different ways You can choose "Spelling..." (or hit apple-:) from its special place where it lives in the Edit menu next to its brother, the Find/Replace Text Service (which does not have a catchy name), and it opens up a little stereotypical spell checker box; but, Applespell also has a check-as-you-type feature that can be turned on or off at will. Mistype a word and it lights up in red; right-click (or control-click if you have a one button mouse) on any misspelled word and it will display a list of possible alternatives; press apple-; (or hit "Check Spelling" in the menu) and it will jump to the next spelling error within the text field.

Now, there are a couple issues with the dictionary, which seems to have been randomly grabbed from an old version of ClarisWorks at the last minute; the number of common words it does not contain is horrific (for example, 'horrific', 'internet' and 'AppleSpell' must all be added by hand, which is as simple as a right-click-- see the ~/Library/Spelling/ dir-- but still obnoxious) and there are quite a few longer words that i have spelled correctly only for it to mark it as incorrect and suggest literal gibberish as the only correction. And i would prefer to have a choice of British vs. American spelling dictionaries (Although i'd imagine the "international" version does already). This is all forgivable, though, considering i am using a Beta release of Mac OS X and this is a new, unpolished feature.

Still, consider: Just now, i managed to go back and fix ALL the spelling in the first 160 writeups in my EUS ("Oldest First") in under half an hour. I would open them one by one, drop into the Enter your writeup box, use apple-; to cycle through all the unrecognized words in the writeup and fix all the legitimate mispellings, sumbit, then close that window and go to the next. I felt really groggy afterward, but it was that simple.
Impressed yet?