Last month, Facebook announced its new chatbot platform. Jarvis is one of the early entrants, allowing you to set reminders with a chat conversation directly inside Facebook Messenger. Right now, the bot is pretty rudimentary. When you first speak to it (it's gonna take some time to get used to this), it will ask you what city you're in to set the time zone. After that, you can send it a message like "remind me to buy eggs tomorrow afternoon" and it will remind you to do so. You can also write "help" to get options to review your reminders or change your time zone.
At the moment, Jarvis doesn't seem more powerful than the kind of reminders you might find in Google Now or Siri. However, it's a neat way to demonstrate what Facebook chat bots can do. It may also be easier for the less tech-inclined to deal with reminders in a conversational way.