Letter to Yourself - Send a physical letter to your future self

Workflowy - A better way to organize your mind.

Future Me - Send an email to your future self

Dynalist - Dynalist is a web app that lets you break down and organize your thoughts in the format of lists.

Letter to my future self - Letter to my future self is a prominent email scheduling service that gives you the opportunity to create a letter with goals and thoughts for your future self and schedule a date for sending it.

Taleguild - Web application for short story writers and essayists