I put together a detailed follow-up on the KISSmetrics/Hulu respawning mechanisms outlining exactly how they work (although this is probably pretty basic for most the audience here).
Also nikcub - very enlightening about the Last-Modified header! It reinforces my point that the solution to all this might not be technical but require policy guidance as to best practices, etc.
we're planning to follow up with a post that has the technical details of the Etag stuff (sorry about 'light on detail', it was a press piece after all).
you're right in that it's been a known method that has been written before (samy had it in evercookie which we site in the paper and a few others have blogged about it). what seemed new (at least to me) was actually encountering it 'in the wild' on a top50 site like hulu. if this type of thing been written about before, definitely let me know so we can cite it.
fwiw, yes noscript would block the javascript that kissmetrics uses to respawn using html5/etags, however there's still the swf that regenerates using flash cookies. also josh highlights ways the you could do this with javascript disabled using CSS (kissmetrics actually also uses hidden values in CSS as well if you look at the src)
either way, blocking javascript/flash would render hulu, and other 'rich media' services like it, largely useless unfortunately.
RE: foxnews/polldaddy. actually they were naming their database 'evercookie' some time ago although they've seemed to have changed that (now it's just called pd_poll__). you can see the script they use here which they use html5 and swf databases: http://pastebin.com/0ieZ2i22 (prettyfied from http://static.polldaddy.com/p/4424060.js )
it's likely that polldaddy/foxnews are using these techniques so to ensure that a given computer only gets to vote 'once'. however, i think there are probably much better ways to do this.
hope that helps. i'll link a blogpost down here somewhere (which means that i actually have to start blogging finally ;)
Details here: http://ashkansoltani.org/docs/respawn_redux.html
Feel free to send comments/suggestions.
Also nikcub - very enlightening about the Last-Modified header! It reinforces my point that the solution to all this might not be technical but require policy guidance as to best practices, etc.