You may have seen the recent news of a move towards using USB as a power source for a “universal charger” for cell phones, cameras, GPS units, and similar devices, “Industry agrees on unified cellphone chargers”. I had been following this development for a while and when I saw the latest news, I had two thoughts.
First , what took so long? It's a very logical and sensible idea to use USB as a charging source, as long as you can accept the current-supply limitations (and many devices can). Regardless of whether the incentive for doing this come from zealous regulatory agencies in the EU, or simple consumer desire to cut back on the number of chargers they need to lug around and not lose, doesn't matter
Second , this is a clear demonstration of how hard it is to foresee where technical developments will take us, which is a corollary of the larger Law of Unintended Consequences. (Aside: this was referred to by James Joyce's in his epic work Ulysses as “the imprevidibility of the future”, with the small joke that Joyce made up that word, but readers can figure out what he meant from its roots and the context),
When the USB standard was first established, its primary role was to simplify and unify the interconnection between a PC and its key peripherals: keyboard, mouse, scanner, and similar. As USB became more common, it was adapted for higher-speed interconnections as well, and we are now seeing USB 3.0 coming into play.
Whatever was in the minds of the USB developers, we heard little of using USB as a basic power supply, with its data lines irrelevant. But over time, the ubiquitous adoption of USB, plus improvements in USB power-sourcing ICs and USB line protection, has made it a power rail as well. And the consequence of being able to use a USB port, whether from a dedicated “wall-wart”charger or from a PC port, to charge our many small devices is a good thing for user convenience and simplicity.
But I am not so sure about the worth of all those USB-powered gadgets I see in catalogs such as from Extreme Geek. After all, running those little fans and reading lights from the PC's USB port seems swatting a fly with a mallet! ♦