TikTok has 1 billion DAU; 3% upload, 2 videos each, average length 30 seconds. Storage keeps 4 encodings (original + 3 variants), each at 1 Mbps (= 125,000 bytes per second of video).
For egress: at peak, 300 million concurrent viewers each stream at 1 Mbps.
Use: 1 day = 86,400 sec ≈ 10^5 sec. Powers of 10: 1 KB = 10^3 B, 1 MB = 10^6 B, 1 GB = 10^9 B, 1 TB = 10^12 B, 1 PB = 10^15 B. Bandwidth: 1 Mbps = 10^6 bits/sec, 1 Gbps = 10^9 bits/sec, 1 Tbps = 10^12 bits/sec, 8 bits = 1 byte.
Compute uploads, ingested video-seconds, daily storage, and peak egress.