[jarkko]

Original author here.

I don't think we really disagree there. I might not have made it clear enough, but I mentioned that there are obvious things that need more consideration, like Kissmetric's or Skylight's data aggregation and massaging.

That said, for many (most?) that culprit is not easy to identify in the early stages and many apps are still basically glorified CRUD apps where that is a non-issue to begin with.

For example, a few years back we ran a much publicized vote for an unidentified social network with more than a billion users. It ran on a run-off-the-mill Monorails[1] app and MySQL, without any hitches. If anything, we vastly overestimated the number of app servers needed (a couple dozen IIRC).

Of course it was a fairly simple use case, just an example that high load by itself doesn't mean much.

[1] A term commonly used for a web app that is a single Rails application, as opposed to a more SOA-style app split in smaller pieces.