I was doing some regression testing today on foundeo's feed parser for ColdFusion today, and when I saw some posts today on Yahoo Pipes, so I thought I'd add one of their RSS feeds to my test harness.

When I ran the test I found that the dates were not parsing correctly. After a closer look at their RSS 2.0 feed I noticed that they are formatting dates using ISO 8601 (for example: 2007-02-22T20:06:31.0-00:00).

I know what your thinking: An RSS 2.0 feed using an ISO 8601! Everyone knows RSS 2.0 uses RFC 822 for formatting dates (eg: Thu, 22 Feb 2007 20:06:31 GMT)! ISO 8601 is used in Atom and RSS 1.0 feeds. Ok, you probably weren't thinking that, but if you had been messing with RSS feeds today you might have.

A quick run a feedvalidator.org will confirm that RFC 822 is required for RSS 2.0. It's just a little suprising that Yahoo didn't do that before launching this awesome service!