Portable electronic keyboards have been evolving for decades. In 2009, the best examples can reproduce traditional instruments, such as pianos and organs, with great detail. They can also create totally new sounds.
Musicians routinely use laptop computers onstage. Virtual instrument software creates sound in real-time, and can be controlled by musical keyboards and other devices.
Simple electronic guitar effects, like wah and fuzz, have been around since the 1970s. Today, musicians use more sophisticated processing, such as delay and flanging. Better electronic devices made this possible.
Because of the miniaturization of circuitry, manufacturers can make smaller microphones that still sound good. Performers can use wireless mics, giving them the freedom to roam the stage without tripping on cables. Microphone headsets free up their hands to play their instruments.
Sound mixers depend on clean, accurate audio electronics. Improvements in silicon chips have allowed smaller, better-sounding, and less-expensive mixers. It's common to see musicians using several at the same time.