How to Deal With Technical Debt

Twitter had no clue how many users do we have. So it's a difference if I have a thousand users or a million or a hundred million users so you have to start somewhere. One thing to deal with technical debt is to ask the question which parts of the system are really important concerning changeability. You might get that information from historic data like where were the last few changes? Or you can think about it more from a business perspective. Which parts if we can change them quickly will give us a competitive edge.