The practice of browsing the Web with many browser windows open. Right now I have five, but only because I just closed three.
I start out trying to handle pages with lots of links on them (like search engine results, pages of thumbnails, or just about any E2 page). I end up doing about twenty different trains of thought at once.
Power-surfing is useful on slow connections, so you can read one page while the next six download). A bad side effect is that it's easier to switch out of a mental process than back into one.