
I don't see the point in an interested parties list, hard enough to keep track of people you are actually willing to let gave a pup.
People who have a casual interest I send to the breed club for the puppy/planned puppy list that the club secretary has, or suggest they contact me when I have the pups to see if there are any left.
If my bitch hasn't even come in season then I suggest people contact me once I ahve mated the bitch, unless they are after a pup from specific parents then I woudl as soon put them in touch with someone who ahs a pup left or whose bitch is due shortly.