One potential business to attract is the publishing industry. Today, publishing is concentrated in New York and the New Jersey suburbs, where books are printed and stored and recycled after being returned. So long as the industry is dependent upon paper, there is little reason for it to move from that region. There is ready access to a pool of experienced workers, for editing to manufacturing to shipping.
But assume e-commerce reinvents the publishing industry. Sometime in the future, the intellectual property of authors could be distributed through the Internet rather than through paper. Readers might download just the assigned chapters of a textbook. Perhaps they will purchase rights to a whole novel, but those rights would expire in a month. The file could be stored and replayed (perhaps as an equivalent to an audio tape) via whatever e-book tool finally becomes a commercial success.
Then the manufacturing and shipping infrastructure in New Jersey would become an expensive and unnecessary appendage to the publishing industry. The high-value component - attracting and editing and packaging and marketing an author's product - could be located elsewhere, far from the high-cost base of operations in New York.
What would keep the publishing people in New York anyway? There is a critical mass of publishing expertise already there, with all the associated support services - restaurants, coffee shops, museums and art galleries, much of whatever you might consider to be intellectually stimulating is located in New York City. If you want to do business, New York is a convenient - and central - place with all the pieces.
If a second center of skilled personnel developed elsewhere, and there was no longer a physical advantage to being in the New York area, then the other location might gradually attract some of the publishing specialists and some of the business. And in the Northern Virginia region, there is a critical mass of communications specialists, from the telecommunications technologists to the political spin doctors. And though the museums and art culture of the area is far thinner than what's available in New York, there's enough to suggest Northern Virginia could develop a strong e-publishing sector in the economy over the next 20 years.