I have flash on my N1 too (froyo), but it's definitely noticeable when the webpage has flash on it -- even when it's a tiny flash ad somewhere. Scrolling the webpage becomes really choppy -- sometimes I wish I could disable all flash except for when it's used for video.
It does, but at the page level. If a page has seven flash elements, once you activate any of them it activates all of them (as the activation is of the plug-in rather than the instance). I suspect this was by design, as the thought would be "make compelling flash content and then we'll also get them with the flash ads".
uhm.. yes you can.. and i think that's the only thing to do when you want to have a decent webbrowsing and flash experience.
In the browser options you can disable plugins. You'll have to press the area of the plugin to make videos and games work, then. Disables all those flash ads, though.
