It's unclear how the technology is being implemented, but we were promised it wasn't just video tricks and was indeed a video of a lab demo.

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While this means they have a similar role to the guided missile cruisers, destroyers are smaller and faster and are designed to reduce their profile on enemy radar - though it is unclear whether this technology is successful.

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It was unclear whether any search technology from Yahoo is powering Etao's search services.

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For all its promise, just how fast the technology will spread remains unclear.

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It is unclear what the acquiring company will do with the technology.

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And it is unclear to me that there is any kind of technology we could come up with that could keep an appreciable number of them out.

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And the technology has had teething troubles, so its future is unclear.

ECONOMIST: MONITOR