Some innovations change everything. The rise of personal computers in the 1970s decimated the mini-computer industry. TurboTax forever changed tax accounting, and MP3s made libraries of compact discs obsolete. Even venerable public institutions like the United States Postal Service, which reported an $8.5 billion loss in 2010, are not immune. It experienced a 6 billion piece decline in mail volume that fiscal year, thanks mostly, of course, to email.

These innovations bear the traits of what Harvard Business School Professor Clayton M. Christensen terms a disruptive innovation. Disruptive innovations fundamentally transform a sector by replacing expensive, complicated, and inaccessible products or services with much less expensive, simpler, and more convenient alternatives. This pattern is as common in heavy industrials as in professional services, consumer packaged goods, and nonprofits. In one of its most recent manifestations, it is little by little changing the way people think about education.

via The rise of K-12 blended learning: Profiles of emerging models | Innosight Institute.