The last few years have seen an explosion in ways of going wireless - in everything from light switches to battery chargers, wires are starting to look distinctly 20th century. But leaner times will force wireless technologies to prove their value, and not all of them are going to make it.

There is an argument that an economic boom-and-bust is useful in allowing investment in innovation that can then attempt to prove itself viable beyond the boom. The first transatlantic cable failed within a month, but a sustained economic boom enabled a (second) replacement to earn $1000 in the first day's operation. Eight years later, in leaner economic times, an iceberg-crushed connection was repaired within weeks - the innovation had proved itself an essential part of Victorian life.

Some technologies, such as the proximity systems used for pre-paid mass transit by Oyster and its ilk, have proved their value and aren't going anywhere - the infrastructure has been built and the investment made. But others, such as the much-discussed white-space devices soon to become available in the USA, are running out of time to get themselves integrated into life as we know it before investment looks like inopportune extravagance.

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