The first stamp in the world was issued by Great Britain in 1840, and ever since British Area philately has been the most popular specialty worldwide. By 1900, over 300 entities owed allegiance to the British Crown and had issued postage stamps. Some, such as Canada, were significant major first world countries. Others, such as Tasmania, New South Wales, or Jammu and Kashmir were component states of larger countries such as Australia and India which hadn’t confederated yet. Still others were smaller colonies that had British government such as Antigua and Seychelles. And lastly, there were the numerous colonies that represented political statements by the British foreign office—places like Zululand—which retained local government with a light British political overlay as the London government attempted to improve its political 
position among its European peers.
From the earliest period, British Empire stamps have been most popular. They were always well designed and, except for watermark changes that philatelists count as separate issues, the same sets were in use for long periods of time. Most are reasonably priced, but most colonies also have high values that are rare and pricey. British Colonial stamps solidified their number one philatelic position by 1950. With Europe devastated after WWII, the prices of European stamps fell in price. British stamps, which had always enjoyed a more active worldwide market, continued to be popular and rose throughout the 1950s and 1960s (it wasn’t until about 1970 that German stamps regained their 1938 price levels). Today, collectors in Russia and China—two of the world’s most nervous economies—are the most avid collectors of British stamps. One suspects that they are indulging their hobby and placing funds outside the vicissitudes of their currencies and economic conditions at the same time.