There was a topic on the old forum opened by @glo, who wrote:
so far i received 11 postcards from the official postcrossing. and i all have the twins number.
example: 7955 (the 5),6995(the 9),6562(the 6), etc
but i also got some unique numbers like :
PT-5656 from portugal, and DE-9889 from germany and sent ID-1 as the first postcrosser from Indonesia & ID-88 a lucky number according to chinese beliefs
how about all of you?? did u get some unique numbers too?
example: 1234, 5678, 7000, 8888, 1001, 2233, 6969, etc
Shall we continue it here?