A number of people wrote to whack on me for claiming the Tab key was related to the metal tabs on a mechanical typewriter, saying instead that it is short for "tabulator," a device for making tables. In that sense the key name still makes sense on the computer keyboard, although I wonder if people would have thought that before Word came up with its table feature. On systems with monospaced fonts (and even on Macs with proportional fonts), many people still use the space bar to make tables.
Avoid Simple Typos
If, like me, you find yourself typing 2911 in place of 2011 entirely too often, you can have Mac OS X (either Lion or Snow Leopard) fix such typos for you automatically. Just open the Language & Text pane of System Preferences, click the Text button at the top, and then add a text substitution by clicking the + button underneath the list. It won't work everywhere (for that you'll want a utility like Smile's TextExpander), but it should work in applications like Pages and TextEdit, and in Save dialog boxes.