How many minutes does it take you to ride an elevator to reach your colleague's desk in a large office building? After you wait for an elevator and stops at other floors, perhaps 3, even 5 minutes? A SkyTran system traveling at 100 MPH point-to-point could transport you anywhere in a dense city such as Manhattan in that time. A large company will not need to concentrate its people in a single large building such as the World Trade Center. They can rent hundreds of locations all over town; yet to the employees, it will feel like a single office where they can be physically present in minutes with any other employee for a meeting or just to talk out a problem face to face.
Email and chat and videoconferencing go only so far. We are primates, not robots, and there is something about physical presence that no amount of virtual interaction can duplicate. When all the employees living within a 100-mile radius can physically come together with less inconvenience than commuting to work today, there will be much less need to settle for pale virtual substitutes.
However, note that physical presence is not a possibility for employees 1000 miles or half a world away, whom virtual collaboration puts on a much more equal footing. (My software consultant friends who enthused in the early nineties about logging in to their clients' computers from the back woods of New Hampshire or Oregon were much less happy about programmers at a fraction of their pay scale logging in from Bangalore, India.) Business is likely to become much more integrated on the scale of 50 or 100 kilometers, and as a result somewhat less likely to diffuse around the planet.
There are many possibilities. How about a New York City department store with Women's Clothing in the garment district, Fine Jewelry on 5th Avenue, and Sporting Goods in a warehouse in Queens? Just as they stamp garage tickets today, the store would probably pay the fare for customers to board a SkyTran from one "department" to another, arriving in a similar amount of time they currently require to go between floors in a large store today. Or how about a virtual shopping mall? In the time it takes you to walk from Sears at one end to Filene's at the other, you could be at any of thousands of cooperating stores, restaurants or specialty boutiques throughout a metropolitan area.
All this flexibility would make a single enterprise more efficient. Even more interesting, it would enable FrictionFreeCapitalism. After many years, it will enable cities to develop to almost any desired density without being limited by transport between tall buildings -- see HowDenseCouldCitiesBe.