Comment by datan3rd

Detailed web event telemetry is where I have seen the "biggest" data, not application-generated data. Orders, customers, products will always be within reasonable limits. Generating 100s of events (and their associated properties) for every single page/app view to track impressions, clicks, scrolls, page-quality measurements can get you to billions of rows and TBs of data pretty quickly for a moderately popular site. Convincing technical leaders to delete old, unused data has been difficult; convincing product owners to instrument fewer events is even harder.