I think it is a perfect application for that stack because it gets nearly 100% uptime and durability without having to worry about keeping a server up. Even if I was handling 1000 requests a day, it wouldn't be worth keeping a server running, but if it grows I can scale it up quickly by just turning a few knobs.
I tag links in Pinboard, then have a Lambda that consumes them into DynamoDB. Other Lambdas build out snarkive.lastweekinaws.com, the weekly newsletter template population, and setting static headers for CloudFront.