When Cloudflare has a high-profile client, they'll often blog about it. It's a smart marketing technique, because they lift on the publicity around the client.
This scenario is actually daunting for most small sites: it's four days out, you're about to get tons of traffic, and keep it to yourself :)
Setting up Google-load-capable infrastructure in 4 days is trivial for some you on hackernews, but non-trivial for others.
Cloudflare sounds like a convenient, drop-in solution for when you don't know how to configuring your own reverse-proxy.