Slackin - Create your own public Slack chat community
Letterflix - Send letters and snail mail online to the USA, Europe, India, or anywhere in the world. Letterflix is the easiest and secure way to send letters and snail mail anywhere in the world from the comfort of your home.
Mio - Powering seamless communication between workplace chat apps.
DocuPost - Sustainably mail letters, checks & postcards online from 75¢
Chats.Directory - A curated list of the best Slack groups for professionals
Letter to Yourself - Send a physical letter to your future self