CDN is a way to store static assets and serve them up from an area like the edge closer to the user, right? So you're having, you're distributing your assets across all these servers. And in addition, there's also CI continuous integration or CD, continuous deployment tools. Cron jobs are jobs that will run every so often; for example, at 4 AM we might want to pull an API and check for new instances of something. It's funny, not all of these services support this type of thing where you need to run some specific code every couple X minutes, hours, days, whatever.