There is “Send to the Future“ button and it can be found at http://www.futureme.org/ - you can write an email and send it to your own address with the option to be delivered on a designated date in the future.
The owners of FutureMe advertise their site: “send your future self some words of inspiration. Or maybe give 'em swift kick in the pants. Or just share some thoughts on where you'll or what you'll be up to in a year, three years...more? “
You can make your letter private or public. If you choose to make it “public but anonymous”, your letter will be published in public letters section of the site, without your address and only if no specific people are mentioned in it. Reading other people's public letters is quite interesting and also usable with students for different reading tasks, discussions and other activities.
FutureMe seems a nice tool for writing, to use with groups of students we are going to teach for a longer period of time, when we set some objectives at the beginning of the course and want to check them after some time.
Also, if you are reflecting on your participation in Blogathon this year and making some plans and decisions for next year, maybe it's time to write a note about your present thoughts to FutureYou and get a surprise from the past on the first day of the next Blogathon. Emails are much more accurate than memories.