Tusulog complements email and more but we honestly don't think email can replaced completely. It's a simple product that sends and receives messages between people. What it does:<p>First it turns the basic idea of email upside down that's anybody can send mail to anybody's inbox. With Tusulog messages from people you don't know goes to Public Pipe and also you can disable it altogether. BTW, your friends can send to your inbox directly.<p>Second with email you apply the filter after getting the message. With Tusulog you apply the filter (pipe) before. PG, taking your example literally: You create a TODO Pipe with public_key THEPUBLICKEYOFPGSTODOPIPE. You give this public_key to people you want. They can send message to that pipe in other words they can put a task into your ToDo list. They can do it using Tusulog UI or Tusulog API.<p>edit: added linebreaks