scripts and bookmarks
One problem comes when scripts and some kinds of dynamic content
make it impractical to restore the state of a compound document.
This is a major drawback for hacking documents with scripts, and
I think should be made clear to the user so that she or he knows
that the current state can't be bookmarked. Users can then vote
with their mouse on whether to tolerate this for "normal" pages.
Scripts should be able to participate in the bookmark process.
They should be able to be asked for bookmark information and be
able to restore their state given that info.
Not all scripts will be able to do this, but I think a good number
would be able to benefit from that capability.