Last time, wicked thunderstorms took down Amazon.com's (AMZN -2.56%) East Coast data center. This time, with nary a cloud in the sky, failures in multiple cloud services caused trouble for a variety of Amazon Web Services customers, including location-based social network Foursquare and salesforce.com's (NYSE: CRM) Heroku online application development platform.

Outages like this are bound to happen. This is the Internet, after all, a fully distributed system designed not to operate flawlessly but with enough redundancy to withstand all but the most cataclysmic of national disasters.

Performance was never the point. It was only when enough of us began using the Internet that performance became the point, giving birth to the likes of Akamai Technologies (NASDAQ: AKAM) and AWS. Yet all networks have limits.

Here, instances of Amazon's Elastic Compute Cloud and Relational Database Service suffered "degraded performance" and "connectivity issues" from the late morning through at least the early evening, according to the AWS Service Health Dashboard.

At some point Amazon will figure out exactly what went wrong. We in the media will then get the results and toss them about like a salad, wondering aloud why the e-tailer didn't do things differently. But that's hardly the point.

The lesson here is that AWS is just as vulnerable as any hosting service, including its main rival: Rackspace Hosting (RAX). And you know what? That's fine! In fact, I suspect a plurality of start-ups and more than a few mature Web operators use both AWS and Rackspace as a failsafe for unforeseen conditions.