Yesterday Bill Rawlinson, the elmcity curator for Huntington, WV, noticed something odd about an event that showed up on Eventful.com:

Here’s the example: http://eventful.com/huntington/events/allman-brothers-/E0-001-020736056-0. It appears the Allman Brothers were in concert today, but I’m pretty sure they weren’t.

I’m pretty sure they weren’t either. At AllmanBrothersBand.com it says they were in Nashville on October 14. But if that’s true, Eventful isn’t the only site that got it wrong date. So, apparently, did a number of event-gathering and ticket-selling sites. Here are couple of examples I found.

In cases like these it’s hard to nail down the provenance of a “fact” such as Allman Brothers, Huntington WV, October 14 2009. There is clearly syndication going on, but who’s upstream and who’s downstream? How is the network of feeds interconnected? Which is the authoritative source?

I know what the answer to all these questions should be. The Allman Brothers themselves should be the authoritative source, and everyone else should syndicate from them.

If AllmanBrothersBand.com published its schedule as calendar data rather than as calendarish web pages, the organization could control the data. Was there originally a concert planned for Huntington on the 14th? I don’t know, but say for the sake of argument there was. The Allman Brothers calendarish web page cannot effectively propagate a change of plan.

An iCalendar feed, on the other hand, could. But calendarish web page are almost never alternately available as machine-readable iCalendar data that can reliably syndicate.

Looking under the covers, I see that AllmanBrothersBand.com is a PostNuke site. Are there calendar modules for PostNuke that export iCalendar? None of the ones that I found seem to.

Why don’t more content management systems make event information available as useful data? Why do they instead advertise things like XHTML compliance and not-very-useful RSS feeds? Because, chicken-and-egg, nobody ever seems to expect an iCalendar feed.

If we can change that expectation, a nice chunk of the real-world semantic web will fall into place. And it won’t require RDFa or SPARQL or ontologies. Just good old RFC2445, right under our noses the whole time, if only we would open our eyes and look.