I once stumbled on a story from the era of workers’ competence in Silicon Valley being measured through brainteasers: (paraphrased, recited from memory)

Let’s ask a candidate: “Alice would like Bob to call her in the future and Alice would like to keep her phone number private. What should Alice do?”

Microsoft would want you to elaborate cryptographic scheme for Alice and Bob to communicate secretly.

However, Google would want you to start with: “Alice should tell Bob to call them, and provide backup plan if Bob has trouble doing so.”

Every now and then, I think about this and how my impression of the author’s tone is more about showing the culture at the two companies instead of a puzzle worth solving in an interview.

Today, something else clicked in my head: the supposedly Google-way of doing it somewhat resembles how content delivery network (CDN) works — make a request with ETag attached (using If-None-Match header) and server will respond with HTTP 304 (i.e. “you are up to date!”) or content with new ETag will be served in the reply. This allows the potential to save up transfer cost of files from server.

This is partially relevant to human interactions too. No hello is often favored to reduce the expensive communication overhead.