There seem to be endless amount books on startup and launch growth, but I'm looking for information on how to optimize once you already have a large user base. I'm comfortable with A/B testing - I use Optimizely at my current job, but I'm far from an expert. I also have a background of being a data analyst, so SQL, Python, and GA are things I often use in my day to day. What would you recommend for someone who wants to potentially land a job at a large tech company? How do you work and test around massive datasets? I'm assuming that the hacks in the startup world might not be as beneficial here, but that could be wrong too. I feel like I haven't seen/read much about retention either. Please let me know if you have any recommendations for me! Thanks!