How many types of salt are there?

Obviously, when we talk about salt, we're actually talking about a whole family of salts.  WhatscookingAmerica.net describes three main types:  table salt, kosher salt and sea salt.  The first two are harvested in the mines with water (i.e. creating a "brine"), while sea salt comes from--well, you know.  Kosher and sea salt are coarser and are generally agreed to have a more interesting, brighter flavor than table salt. Each of these three categories then get broken down further into subtypes.  Sea salt, for example, comes in a multitude of varieties, each distinguished by where it's from and what minerals are mixed in with it.

Then there’s iodized salt, which has an additive, a trace element (iodine), that’s needed in the human diet and may be lacking in some people’s diets.

And there’s epsom salt, which is a completely different compound that just happens to look like table salt.  It is an effective laxative, and thus NOT an acceptable substitute in recipes, except possibly on April Fool's Day. 

Warning:   Dead  Sea salt, widely used  for bath and beauty products, should not be consumed.  The Harvard Heart Letter (July, 2010) reported the following: "A man who consumed it for several months after reading online that it had calming effects  and other health benefits became confused and disorganized and developed slurred speech and mood swings. His doctor realized that he had bromide poisoning."  Salt extracted from the Dead Sea contains large amounts of bromide.