Seriously? That sounds odd I'm running the latest version of Flash in Firefox and it is using between 0-6% CPU with 8 tabs open including this Flash chart.
If he's using a laptop, he's now burning significantly more power. 4 hours of battery life at idle can easily become 30 minutes at a constant 25% CPU load.
you're already looking at HN, it's not like you're really gonna need that 25 for anything else right?
Actually, I did need that 25% for something else. Was waiting for code to finish compiling (well, for Clang's Static Analyzer to finish running). It takes more then a few minutes to run on a sizable project.
Plus, as jrockway pointed out, it absolutely kills battery life, and I'm on a laptop.