Every once in a while I get PMs with questions like: I signed-in for the MAX but I only have that and that number of addresses on my list, is that OK?
Let me try to explain and I will add this to the description for future rounds.
The postcard exchange is a real exchange. That means you should receive a postcard from everyone on your list. That would be easy if everybody would sign-in for the max. But we decided to allow to limit the number of postcards - for good reasons I think since this allows people with less printing capacity (be it because of time or money or whatever) to participate as well. Now if we have 40 participants and one of them would only sign-in for 10 postcards, then that guy would also only receive 10 postcards and there would be 29 participants who would not send a postcard to this guy and therefore not send the max.
However, I tried hard to optimize my little program and so we usually end up near the theoretical optimum. E.g. With the data for this round we send out 1190 postcards. The theoretical optimum would have been 1215 postcards. So we are just 2% off which is not too bad. And it is unclear if there would even be a possible mapping to reach the optimum.