A Look Back at the TR10
Your list of 10 emerging technologies (“TR10,” March/April 2009) was interesting, but sometimes implausible as well. Grant me an indulgence and do this one small exercise.

Revisit the technologies you’ve profiled in previous TR10 issues–say, in 2006 or 2007. I think it would be quite startling to look at how many of those technologies given high praise have died, mutated, or become terminally stuck in an incubation period. How good was TR at making the right picks?

The struggle to nurture a good idea from something theoretically possible into a working prototype is child’s play compared with the endless real-world demands one must break through to get something produced and into the public arena.
Guy Munsch
Silver Spring, MD

The editors respond:
If we do as Mr. Munsch suggests and look back at our 2006 and 2007 issues, we see that only a few entries (nuclear reprogramming for stem cells, augmented reality for cell phones) have made clear progress. But the TR10 are emerging technologies–which, as he says, are unlikely to be overnight successes. It’s not surprising, then, that when we examine the first TR10 lists we published, in 2001 and 2003, our performance looks better. Many of those technologies are well on their way to becoming commercial successes, if they haven’t already arrived: data mining, biometrics, microphotonics, microfluidics, wireless sensor networks, grid computing, and mechatronic braking systems, to name a few.

But Who’s Counting What?
In his article about the difficulty of measuring online audiences (“But Who’s Counting?” March/April 2009), Jason Pontin made the case that media companies, and the advertisers they wish to attract, need better tools for measuring how many people are visiting their sites. But while numbers of visitors are important, the most important numbers for advertisers come in the form of dollars, euros, and pesos. What we need is reliable measurement of how much money can be made from sales by advertising on a given media site. The lack of such information has enriched many a media-industry Madoff in my country of Mexico; a standard measure of the impact of advertising online would help prevent this preposterous transfer of money.
José Luis López-Léautaud
Cuajimalpa, Mexico

A Nuclear Debate
I was heartened to read Andrew Kadak’s short piece arguing that nuclear power must be understood as environmentally friendly (“Green Nuclear,” March/April 2009). When I managed plutonium manufacturing at the Nuclear Materials and Equipment Corporation (NUMEC) during the late 1960s and early 1970s, we proved that fuel recycling was accomplished easily and that breeder reactors were well suited to that end. We provided fuel for the Fast Breeder Critical Assembly in Japan and for the Zero Power Plutonium Reactor and the Fast Flux Test Facility in this country. Fuel recycling is the way to go!
Bill Frankhouser
Elizabethtown, PA

As a student of nuclear energy at MIT, I am as pro-nuclear as anyone, but I find fault with the assertions of Andrew Kadak and John Gilleland (“Traveling-Wave Reactor,” March/April 2009) that we need to develop new breeder reactors to extend the resource base of nuclear power. Fuel composes only 10 percent of the levelized cost of nuclear power, and of that 10 percent, only half is spent on the uranium itself. Furthermore, with uranium at under $130 per kilogram, we have nearly a century’s worth of reserves. With minimal exploration, we could easily discover another century’s worth at that price; from 2003 to 2005, the world’s known reserves doubled thanks to just such an effort.

When will the uranium misers realize that they’re solving the wrong problem? Their efforts would be better spent on reducing the capital costs of nuclear power and leaving fuel utilization to another day.
Keith Yost
Somerville, MA

Out Of This World
I read the January/February 2009 issue on my flight home from South by Southwest (the magazine was part of the conference’s swag bag). There wasn’t a weak story on any page, but one was out of this world: Adam Fisher’s oral history of space tourism (“Very Stunning, Very Space, and Very Cool”).

While I’ll probably never have the millions to afford a flight to the International Space Station, I can rest easy knowing that my $300 three-hour flight in a cramped coach seat was more comfortable than the accommodations afforded professional space travelers. I only wish I had the window seat they had.
Mike Maney
Doylestown, PA

Clarification: The March/April 2009 feature “A Zero-Emissions City in the Desert” does not identify the designer of the Masdar headquarters building. It is the Chicago-based firm Adrian Smith + Gordon Gill Architecture.

How to contact us
E-mail letters@technologyreview.com
Write Technology Review, One Main Street,
7th Floor, Cambridge, MA 02142
Fax 617-475-8043

Please include your address, telephone number, and e-mail address. Letters may be edited for both clarity and length.