As far as I understand it, it's basically feeding small ammounts throughout the day, insted of two or three large feedings. Maybe (what I do for my version of "powerfeeding") 9 meals for the fish, but only 1/4 what you'd normally feed them.
Powerfeeding is feeding every 3-4 hours but is small amounts, and each of those feedings is made up of conditoning foods. These 'powerfeeding' term is used when heavily feeding fish for breeding. But this is not good for long term, IE more than 6 weeks.
Yeah, like what most people say, I feed small amounts, leave them still hungry, and then keep doing that until they stop eating. Then do it again a few hours later. WC is important since lots of food is mixing with the water.