High-Def Flash video is a stretch on some hacktintosh netbooks, but Flash 10.1 brings it into the realm of possibility. I just installed it on my MSI Wind running Leopard, and damn: HD YouTube and Vimeo videos were almost watchable.
I say almost, because there was still some noticeable frame dropping. But still, I could actually watch HD flash video (windowed and full-screen) without it stuttering like a slideshow. One issue with YouTube: the CPU pretty much went into overload once the video was playing, and on the third viewing I had to Force Quit Firefox to wrestle back control.
But this is good news for hackintoshes, and netbooks in general. This is not hardware GPU acceleration (limited to Windows right now), it just seems to be better CPU usage. Earlier today I also posted about AnandTech's Flash 10.1 CPU-utilization tests: they still noticed improvements under OS X, too. If you've given Flash 10.1 a try, post a comment here so other readers can see what sort of netbook you have, and if it's worth trying.
For the record, my MSI Wind U100 has 2GB of memory, a 1.6GHz Atom N270 processor, and integrated Intel 945 graphics. (Pic above is of the Dell Mini 9).