I almost have this working....
I'm using ESI succesfully to display a dynamic poll block for anonymous users on a D6 (pressflow + varnish 2.1) site.
It works fine (voting and displaying dynamic data), except for one thing, when I vote, the form submits to:
and the user is left with a white (unstyled) screen only showing the result html.
I also tried using ajax_poll, but with no effect.
The poll block ESI setting is "do not cache but use ESI". When I disable ESI it works fine. So I guess something gets lost when the block is created using ESI/varnish? Any ideas?