We've all forgotten to do things that we promised to do. Luckily, we have these fancy personal assistants to help us stay on course. Cortana, Microsoft's offering (and whose name is way cooler than the actual product), is learning via machine learning to remind you of things... without you even asking.
I hope you caught my sarcasm. What Microsoft is doing here with Cortana is certainly neat. She can recognize when you promise something in an email after which she will create a reminder for it. If there's a deadline in the message, she'll remind you beforehand. There's not really anything you need to do to set this feature up — just make sure that you've given communications consent. After that, send emails as you normally would and Cortana will have your back.
There are a few caveats, however. This is limited to Windows 10 for now, but iOS and Android will be getting it soon. Also, Cortana can only read emails sent via Outlook.com or a work/school Office 365 account. More email services are coming soon, apparently.
Windows Insider participants received access to this a little while ago, but it's been improved since. Over time, Cortana should get better and better with this. Maybe even enough for me to actually use her.