Starting from the app that requires the most to the lowest at the bottom: Facebook Messenger WeChat (it has something extra called "identifier") Whatsapp (part of the Facebook family of apps) FaceTime (from Apple and it's part of iMessage) Telegram Signal (the only app that does NOT capture data linked
Check out how Bed Bath and Beyond tackles digital customer experience.
A friend of mine is running a start-up in the Silver industry. She provides a SaaS platform that allows family members to care for their elders (e.g.: parents, grand parents, etc.). The company received innovation prizes and grants; additionally, it is in discussion with other companies to leverage that