What Is It
Post Social is a physical social media platform that invites users to interact with each other through letter posts (peer too peer).
Why
The idea behind Post Social is to generate a tactile connection between friends. This might be new for some, or a blast from the past for others. Either way, it seems our world is largely digital, and bringing a physical element into our lives could help slow things down, and allow us to enjoy the moment just a little more.
How It Works
Download the template for your post and print it out.
It fits an 8.5" x 11" piece of paper (portrait).
Folded size approximately 9.5 cm x 14 cm (4.75" x 5.5").
[Alternate Folds are also available]
Ask anyone you would like to send the post to for their mailing address. 
Create your post by filling in the first post box. It should be hand written. Add media (if you want). Stick figure drawings are more than acceptable. It's up to your own imagination what to put there. Taping or gluing other work is also acceptable.
The posts can be light and simple, like "I just had this noodle bowl for lunch" (included with a bad sketch of the noodle bowl). Or, they can be as personal and nuanced as you wish.
Once your post is complete, fold the paper over. A sticker or wax seal can be used to seal the post. 
Fill in and decorate the front side of the letter post as desired.
Place the letter post in an envelope and mail it.
***
If you receive a post (lucky you :) Take the time to enjoy the post and tactile experience.
Once you have absorbed the full extent of the post, create a reply in the empty box that is available.
Once you have replied, re-fold the paper. You can re-seal with a sticker or wax seal.
Mail the post back to the original sender. 
***
When the post is returned, take the time to enjoy the reply :) Keep the post, don't keep it, scrap book it, tuck it away in a drawer. It is your post to do what you want. If it was fun, maybe there will be more :)
+++++
I have also discovered the world of Letterlocking. 
Fascinating folding options can be found there to try as well :)