Stamp collection is considered to be a hobby. Millions of people all over the world collect stamps. For this purpose General Post Office has been set up to help people to collect stamps. Strange stamps are considered to be valuable as they are scarce.
During 1861, the South African post office was running short of stamps; so, a local firm was ordered to print a few stamps. The local firm, by mistake printed one penny Blue instead of Red and Four penny Red in place of Blue. So, these stamps were considered to be rare. People collect such rare stamps for the posterity to see and know its history.
Below Stamp Collecting info from Wikipedia (Read More):-
Stamp collecting is the collecting of postage stamps and related objects, such as covers (envelopes or packages with stamps on them). It is one of the world's most popular hobbies, with estimates of the number of collectors ranging up to 20 million in the United States alone.
Collecting is not the same as philately, which is the study of stamps. A philatelist often does, but need not, collect the objects of study, nor is it necessary to closely study what one collects. Many casual collectors enjoy accumulating stamps without worrying about the tiny details. The creation of a large or comprehensive collection, however, may require some philatelic knowledge.
Stamp collectors are an important source of revenue for some small countries who create limited runs of elaborate stamps designed mainly to be bought by stamp collectors. The stamps produced by these countries far exceed the postal needs of the countries.[citation needed]
Some collectors have taken to philatelic investment.
http://en.wikipedia.org/wiki/Stamp_collecting
