In the Online Contracts App accessed from the in-game smart phone, there are two modes ("Online Tailing" and "Online Hacking"). I assume these are the modes where other players can jump into my live game, or I can jump into theirs.
These modes both say "Complete Online Contracts Introduction to unlock". Where is this introduction?
Note I have just recently unlocked the second area (The Loop), and am at 3/9 in Act 1, for some idea of my progression through the game.