A focused and functional service for event hosts to collect guest photos through a shared link/QR code that leads to an upload page. Think photo gathering for weddings, bachelor/bachelorette parties, corporate events, big birthdays, etc.
There are many of these out there, but I found most unintuitive ("too complicated for Grandma"), too featureful, and/or much too expensive.
MO (mary old), MN (mary now), AO (ann old), AN (ann now)
MN = 24
MO = AN
2AO = MN
MN - AN = MO - AO