I'd probably start with total Gmail users, guess at average emails sent per day per person, then work down to per-second.
Break down the problem into total Gmail users, average messages received per user per day, and convert to per-second rate. Use round numbers and state assumptions clearly, then sanity-check the result against known global email volumes.
Pro tip: Anchor your estimate to a known figure like global email traffic (~300 billion/day) and derive Gmail's share, rather than building purely from user counts—this shows you can leverage external benchmarks.
Define what counts as a 'message' (including spam? promotions?) and confirm we're estimating global Gmail traffic, not just a single region. State that you'll use order-of-magnitude estimates.
Start with world population (~8B), internet penetration (~60% = 4.8B), and Gmail's share of email users (~30-40% = ~1.5-2B). Alternatively, use known figure of ~1.8B Gmail users.
Segment users: active vs. inactive. Assume ~50% are active. For active users, estimate average received messages: personal (~10/day), work (~50/day), spam/promotions (~20/day). Weighted average ~30/day for active users.
Multiply active users (e.g., 1B) by average messages (30) = 30B messages/day. Convert to per second: 30B / 86,400 ≈ 350,000 messages/second.
Compare with global email volume (~300B/day). If Gmail is ~30% of that, it's ~90B/day, which is higher than our estimate. Adjust assumptions (e.g., more active users or higher per-user volume) to align with known benchmarks.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.