Case 3: Online Bill Payment
I must conclude with my favorite new guilty pleasure. When you live paycheck to paycheck, as most of us have at one time or another, the thought of relinquishing control of even the timing of a payment to a large, faceless corporation for "convenience" seems like a cruel joke. The first time you forget that a draft is coming and leave your balance exposed, it barrels through leaving countless fees in its wake. Once you finally reach a point in life where a missing hundred dollars is not a heart-stopping problem, online bill payment is a story of a refactoring triumph.
The complexity, scale, and customer acceptance considerations behind building an entirely new, entirely automated method of paying a bill is staggering. Not only do the transactions have to workcorrectlyevery time, the consumer population at large must believe that they work. Beyond that, all transaction processors (financial institutions) had to agree on a single standard of communication. Ironically, it seems sometimes efforts of this magnitude can gain consensus far faster than even the most academic discussions about XML document format.