The Revenue Society has defined revenue stamps as " ...stamps, whether impressed, adhesive or otherwise, issued by or on behalf of International, National or Local Governments, their Licensees or Agents, and indicate that a tax, duty or fee has been paid or prepaid or that permission has been granted.
Revenue stamps have become less commonly seen in the 21st century, with the rise of computerization and the ability to use numbers to track payments accurately.
In the former British Empire, such stamps were often inscribed "Postage and Revenue" to reflect their dual function.
Some countries such as Great Britain have issued stamps valid for both postage and revenue, but this practice is now rare.
From around 1900, United States revenue stamps were required to be mutilated by cutting, after being affixed to documents, and in addition to being cancelled in ink.
After World War One, however, they declined in popularity, possibly due to being excluded from catalogues as the number of postage stamps issued rose rapidly and crowded revenues out.
The practice is almost entirely stopped now, partly due to the prevalence of forgeries which cost the issuing government revenue.
[11] Governments enforce the payment of the tax by making unstamped documents unenforceable in court.
For instance, the producer may buy stamps from the government which are then affixed to each bottle of alcohol or packet of cigarettes to show that tax has been paid.