I am not sure I understand what we are talking about. If you mean prompting devices like those in video, tv etc use, then no, it is old. But if you mean the trend towards using electronic prompts to remind us, either for simple efficiency or to make more healthy life choices, like take a break from NPs , then that is definitely a growth area and I could see some clever domain names selling in that space. As well as .com, the .me extension would work well imho.
Reads more like a .App than a .Me (even as a personal prompter)
Could you imagine how many times you'd be 'Pinged' every day as you get reminded about everything from buying cleaning fluid to time-sensitive 'Pings' like picking up the kids from school
it's annoying enough just getting the email purchase reminders from Amazon