Hey From The Future is an advice sharing website that allowed users to submit anonymous advice they wish they had at a particular age. Simply sign up with your birthday, and you can submit advice to your younger self, advice for the younger generation, or tidbits of information you want to pass on. Users can then vote on which advice they found the most helpful.
The site costs about $200 dollars a year to run, and is net-negative, but I do consider it to be an important project, so I keep it around. If you feel like donating to support, every little bit helps!
Thanks!