When a site's content is generated by its users, growth is no longer under the creators' control — a large share of it sits with the user community. The Flickr London-subway-bombing spike is the canonical case: an external event drove record traffic overnight, with no warning from the product roadmap. Open APIs compound the uncertainty: your data is consumed by other applications, each with its own usage and growth pattern, plus abuse vectors (a rogue developer crawling the whole database tree). The response is to **monitor API usage** for emerging patterns and rogue consumers, and enforce a Terms of Service. The slope is real — Allspaw's first Flickr year: 60 → 660 photo uploads/minute, 200 → 880 GB disk/day, 3,000 → 8,000 images served/second. Capacity planning becomes important very quickly. --- *Source: [[The Art of Capacity Planning]] (John Allspaw, O'Reilly 2008) — Ch 1 — Goals, Issues, and Processes in Capacity Planning*