tl;dr: John outlines 5 goals for this roadmap (1) create a long term focus for the team (2) evaluate the teams previous efforts (3) create visibility into what the team is focusing on (4) make planning and workload easier to time box and schedule (5) collaborate with other teams and the business needs to prioritize.
tl;dr: C clearly stands out as the "single most important and influential programming language." However, as you work with other languages a tension arises - "you’re stuck either writing bad C code or using poorly-suited tools to interface badly with an otherwise good API."
tl;dr: Three pricing models are discussed - usage based, bucket based and enterprise. Randall strongly advocates for the first as "it heavily incentivizes both the customer and the service provider to act in everyone’s best interest."
tl;dr: The new FB Messenger required a complete rewrite - the codebase shrunk from 1.7M+ lines of code to 360,000. The rewrite was underlines by 4 principles - use the OS, reuse the UI, leverage the SQLite database, and push to the server.