Yes, I wrote a long and embarrassingly soppy letter to myself. I tried to add some value by mentioning a lot of granular detail and links to some websites which mean something to me now, which may or may not still be there in five years.
If you're into it, the main page of the website - https://ohlife.com/ - indicates a range of extra services if you register, up to and including being e-mailed reminders to write more letters to yourself (because they claim that the more letters you receive, the more fun it is!). I'm not quite there yet ... one time capsule from five years back should be interesting, because I think your life changes significantly within five years. One every day from two months ago, not so much.
Here's to hoping we're all still around and happy enough to care about things like this when our e-mails to ourselves land!