Well, I do not mind having this exchange organized outside of APUG and I am going to sign-in after I finish this post. So, if you like to organize it that way, that is how it is. But since you ask about APUG exchanges ...
In principal there are three different kinds of exchanges here:
The blind print exchange where each participant sends the address data to the organizer as a private message. And then the organizer sends around messages who you have to send your print to.
Group print exchanges, there are several and I organize the current small print exchange and also organized some of the lith print exchanges but there is also THE group print exchange and the alternative print exchange. There you sing-up via a message in the thread, then the organizer builds groups of three, four or five people and posts these groups in the thread. Then each participant sends a PM with the address data to the group peers.
The postcard exchange. This is kind of special since it really is more work to do compared to all the other exchanges, but somehow it is also the exchange with the most fun - in my opinion. I organized around 15 rounds of this so I know a bit about how much work it is. In this exchange address data is also send to the organizer via PM and then the organizer sends around PMs with address lists to the participants.
Well, and there is some other exchange I know of which is kind of special, it is the print trade where you trade a print in exchange of an other print, I would have to search for the thread where it is described.
But in none of the exchanges I listed above is address data printed in public. Address data is kept private and since everything is handled on APUG you do not even have to provide an email address. And feedback is given on APUG, how do I do this with your model? You do not ask for the APUG name, so if I provide feedback I have to do so by giving the real name of my peer in public. I know many people on APUG have their real name also as APUG name. But some prefer to not have it that way. Some may not want to send around their email-address etc.
And all that is the reason why I would prefer to have APUG print exchanges kept on APUG - I think it opens up the exchange for more people.