That website in Hedges link looks a bit woo. I thought trace levels of iodine in salt was supposed to be a good thing, but there it is painted as the work of the devil.
I too always wondered why US recipes specified kosher salt, with no reason to suggest that the recipe was otherwise intended/suitable for Jewish people.
But it seems that it's either table salt or sea salt, seeing as different answers have been posted on this thread,
Meh, if I see salt in a recipe, I put in a small amount, and then some more if I think it needs it. Never had things come out too salty.