I do the same as M. I have a standard letter that goes out to people who inquire about puppies ("Thanks for your inquiry...") in which I say who I bred to whom, what color is due and about when. (I usually fudge the date to a few days later so I don't have people calling on the due date to ask if they've arrived yet, and calling while I'm in the middle of whelping!) General updates, photos, and videos are sent by BCC to protect privacy. Private emails answered privately. Phone calls returned asap. After the puppies go home and I send out the occasional group email to the latest litter (birthdays, reminders, general dog info that may be of interest) I still send out with BCC but I address it to puppies by name ("Dear Murphy, Tuckerman, Rocky, Bella, Fisher, Carson, etc.") Families seem to like knowing puppy's siblings' names.

I keep emails conversations private with the individual owners. Once pups are sold, I ask if the owner is open to sharing their contact information with other puppy owners - in case they live near one another, and want to get together for a play date. Most say yes, some don't reply. I do share photos of the pups from the litter (without contact information), since most buyers spend enough tome with the litter before pups go home, and connect in someway to the other litter mates - people are curious how litter mates are doing, and growing.