If you're reading this and doing other things, you're guilty of multi-tasking. Experts say you should cut it out.

No, buying that new dual-processing iMac with the 20-inch screen isn't going to send you to environmentalist hell. Still, as microprocessors, personal computers and servers get faster and stronger, their demand for power grows as well. But while computing potency has been leaping and bounding, efficiency has been dawdling.