Powerpop reached its creative peak during the late 1970's & early 1980's. Regardless of what psuedo-scene girls say...it has nothing to do with hellogoodye and everything to do with 20/20, The Knack, The Raspberries, The Nerves, etc.
Started around the early-mid 70's as a sort of continuation of the spirit of rock played by many Rock and British Invasion bands during the 60's.
Known for it's catchiness and may include 60's-esque Pop vocals and harmonies. Tends to be very poppy, upbeat and fun. Can include elements of Hard Rock and Pop Punk or synthesizers among others. Influenced and related to genres such as New Wave and Jangle Pop, Pop Punk. and Indie Rock.
Tom Petty and The Heartbreakers
But those are just a few and there is many more with much more variety.
Becka: NO!! Head Automatica Currently Owns My Stereo. Powerpop is Love.