from
Jargon File (4.4.4, 14 Aug 2003)
postcardware
n.
A kind of {shareware} that borders on {freeware}, in that the author
requests only that satisfied users send a postcard of their home town
or something. (This practice, silly as it might seem, serves to remind
users that they are otherwise getting something for nothing, and may
also be psychologically related to real estate `sales' in which $1
changes hands just to keep the transaction from being a gift.)
from
The Free On-line Dictionary of Computing (8 July 2008)
postcardware
{Shareware} that borders on {freeware}, in that the author
requests only that satisfied users send a postcard of their
home town or something. (This practice, silly as it might
seem, serves to remind users that they are otherwise getting
something for nothing, and may also be psychologically related
to real estate "sales" in which $1 changes hands just to keep
the transaction from being a gift.)
[{Jargon File}]