The Magic The Gathering ad on the homepage (link) causes the plugin-container.exe to jump up to 53% CPU usage on both my work and home machines. The CPU usage spikes as soon as the fire starts to jump up as shown in the picture above.
It sounds similar to an issue with an older Vindictus banner.
These just kill my performance, especially when two of them show up on the page at the same time.
The plugin-container.exe process pegs at 50-60%, which is symptomatic of Flash taking one of my two cores and EATING IT ALIVE. It gets bad enough that I need to kill Firefox and restart it to do anything (basic browser buttons like "reload" and "back" take 20-30 seconds to register), hoping I don't get two Vindictus ads again.
For reference, running WinXP Pro with an Athlon64 X2 4600+ with two gig of RAM.