I'm generally very sceptical of "start-ups" and I see most of them as bound to fail, but this actually fills a hole. I think this has great potential to make both money and grandparents everywhere very very happy.
My grandpa Tirrell Cook, aka Grandpa Cook, passed away peacefully on April 9th after a tough month-long battle in the hospital. I was fortunate enough to have flexibility in my schedule to be by his side 4-5 days a week. He was truly a great man - I don't know anyone else like him - and I'll miss him dearly. I'm super grateful for all the crazy great times we had the past couple of years. I wrote more about my relationship with him here: https://nanagram.co/blog/on-happiness-from-tirrell-cook
With his passing, I considered putting NanaGram on hold for a while but the feedback from customers has been tremendous, as well as the media: https://mashable.com/2018/04/24/nanagrams-photo-printing-ser.... Plus my Mom, my Grandma, my future mother-in-law, and my Aunt all get a monthly NanaGram.
Great idea
A thing I like about the phone number implementation is I can snap a photo and push it to a loved one (just search their name in my contacts, saved with a NanaGram number behind the scenes) with a few swipes. SMS is the first option on iOS when sharing an image.
We've spent a bunch of time obsessing about notifications and they're not quite where I want them to be yet, but close. I'm not a big fan of addicting apps or services that steal your attention. Every user can tweak exactly what notifications they get. Right now, by default, we notify all the users on an account when a new photo is posted by another user. This is nice since it makes a community of sorts, like a private social network for families. It also helps teach people how the service works. Recently I created a setting allowing you to subscribe to a Saturday morning email instead. This makes for a nice surprise factor, kind of like getting film developed. I'll probably adjust things at some point so all users move off the instant notifications (which help teach people what the service is all about) and onto the Saturday morning digest after a few weeks of using the service.