Scott McCartney, the Middle Seat travel columnist for the Wall Street Journal, and a fellow with whom we briefly rubbed shoulders during last year's FlyerTalk Star Alliance Mega Do, has written an informative column based on a canceled flight he endured in November.
When bad weather or mechanical problems hit, airlines react typically the same. They quickly rearrange aircraft and crews, working to cancel the lightest-booked flights to what executives call "balance" their systems. While cancellations are rare—just 1.63% of all U.S. airline flights have been canceled so far this year, according to Flightstats.com—they're a test of airlines' organizational and communications skills. It's a test that airlines big and small often fail.
Although there are no magic solutions if your flight is canceled (other than it's worth making contact with the airline by phone immediately if you're fortunate enough to have elite status), you'll have a better understanding after reading the entire column here.