Flash 10.1 Beta 3 spreads the hardware-accelerated H.264 video love to more graphics chips, specifically some decidedly less beefy netbook chips: Intel's GMA 500 series and Broadcom's Crystal HD video decoder. Stick with 720p Flash video, and you'll be dandy.
HD Flash video, which has a hearty appetite for CPU cycles, and Intel's Atom, which doesn't have huge surplus of said CPU cycles, have never made a great couple. So Adobe getting serious about Flash hardware acceleration on netbooks is great news! Well, for some. Eventually.