PLK = "PostLagerKarte", literally "mail storage card". It was (abolished 1991) a way to receive letters anonymously; like a P.O. box without your name attached to it. The [Wikipedia page](https://de.wikipedia.org/wiki/Postlagerkarte) even explicitly mentions its "illegal usage in the computing scene", so GP was likely referring to his friend using their P.O. box for (illegally) cracked software.
Here's a shot at translating that Wikipedia paragraph:
> Until their abolition, PLK cards were especially popular in the cracker scene because, compared to a regular P.O. box, no personal data had to be shared with the respective post office. PLKs were primarily used for anonymous sending and receiving of pirated software on floppy disks. [citation needed imho] The PLK addresses themselves were often listed digitally in the cracktros.
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PLK = "PostLagerKarte", literally "mail storage card". It was (abolished 1991) a way to receive letters anonymously; like a P.O. box without your name attached to it. The [Wikipedia page](https://de.wikipedia.org/wiki/Postlagerkarte) even explicitly mentions its "illegal usage in the computing scene", so GP was likely referring to his friend using their P.O. box for (illegally) cracked software.
Here's a shot at translating that Wikipedia paragraph:
> Until their abolition, PLK cards were especially popular in the cracker scene because, compared to a regular P.O. box, no personal data had to be shared with the respective post office. PLKs were primarily used for anonymous sending and receiving of pirated software on floppy disks. [citation needed imho] The PLK addresses themselves were often listed digitally in the cracktros.