Example: "2 years are now a long support cycle for phones as most people get carrier upgrades every 2 years anyway" (from the Android Browser vuln thread. This is only valid in the US because most people in Europe, Africa, Asia, India, etc. buy their phones seperate from their contract, so there is no "automatic" upgrade.
Another example was in the Popcorn-Time threads the "Who needs this if you have Netflix?" – Netflix doesn't even exist in most countries, and where it does exist, they only have like a dozen series, nowhere near the US version, so it provides no benefit. Hell, here where I live even DVD rental is still used, even Amazon provides DVD rental here.
Most of the people in the comments assume that everyone is in the US and a Hacker-News without that would be great.