Both products are made from soybeans.  Soy sauce has a very strong
flavor and tofu is practically flavorless.  Why is this?

Hi stancranley,

Tofu and soy sauce taste different because they are made from
different ingredients by different processes.  Neither consists of
pure soybeans.

To make tofu, soybeans are soaked, mashed, and boiled.  A fibrous
component called "okara" is filtered out and what's left is soymilk. 
Then a coagulant is added and the mixture separates into curds and
whey, much as in cheese making.  The curds are the tofu.  Various
coagulants are used and the choice of coagulant affects the taste of
the tofu, but the coagulant is not a strong flavoring agent, so the
tofu comes out pretty bland in any case.

http://www.tofu.com/whatis.html

http://www.crescentlife.com/dietnutrition/tofu.htm

http://en.wikipedia.org/wiki/Tofu

Soy sauce is made by fermenting a mixture of soybeans and roasted
wheat, or other grain, with salt and water.  The wheat, the
fermentation, and the salt all contribute to the stronger flavor.

http://www.kikkoman-usa.com/_pages/manufacturer/basics/natural_brewing.asp?loc=103&subsection=basics&subsection2=natural

http://www.kikkoman.com/edu/sqa/sqa3.html

http://www.ecomcanada.com/soysauce.html

http://en.wikipedia.org/wiki/Soy_sauce

Your taste buds tell you that soy sauce is salty, so it is no surprise
that nutritional analysis shows that soy sauce contains about 200
times as much sodium as tofu per unit of weight.

http://www.soyfoods.com/soyfoodsdescriptions/tofu.html

http://www.nutritiondata.com/facts-001-02s03dy.html

I hope this answers your question satisfactorily.  If you need any
further information, please ask for a clarification.

--efn

Fully answered my question

Mashed potato and potsheen are both made from potatos
- one of them is highly alcoholic

Fermentation.