Thanks for the pointer to the Signal desktop app! It looks pretty close to what I had in mind. As for the definition of a standalone service: One that doesn't

Thanks for the pointer to the Signal desktop app! It looks pretty close to what I had in mind. As for the definition of a standalone service: One that doesn't tightly integrate with other offerings/ecosystems. Skype is kind of ok because other than connecting with your MS account, it doesn't promote other offerings. Also Microsoft's business model is not based on collecting and selling your data, at least not in the same extent as Google/FB. Web-focused services work ok if you're comfortable with the web. But for parents, grandparents etc., I feel that a standalone client with a simple interface is more foolproof.