Scribbling in the margins of iCalendar

Last week I mentioned three ways for elmcity curators to categorize events:

1. If a source iCalendar feed uses the CATEGORIES property, they’ll be included.

2. If all of the events from a feed can be categorized, you can name that category in the Delicious metadata, using category=CATEGORY. All events from the feed will inherit it in the same way that they all inherit the default clickthrough link specified with url=URL.

3. If all of the events from an Upcoming or Eventful venue can be categorized, you can also name that category in the Delicious metadata. To do that, bookmark the venue URL and use the patterns venue={UPCOMING|EVENTFUL} and category=CATEGORY.

Now I’ve added a fourth. In any iCalendar app you can now use these patterns in the Description field:

url=http://www.harlowspub.com

category=music,bluegrass

The url=… and category=… patterns can occur anywhere in the description.

This is particularly useful for recurring events. As discussed here, recurring events are a great way to build critical mass because your curation effort keeps paying dividends.

For example, one of the events I found when exploring the search page for Keene is the Monday night bluegrass jam at Harlow’s Pub.

Here’s the description I entered into Windows Live Calendar — which also could have been entered into Google Calendar, or any other iCalendar app:

The Birch Benders host a Bluegrass picking party at Harlow’s Pub in Peterborough every Monday night – 8 pm until they kick us out (11 or so). url=http://www.harlowspub.com category=music

Here’s the rendered result:

Mon 08:00 PM Bluegrass night with the Birchbenders (recurring events) (music)

The same data shows up in the downstream XML, ICS, and JSON feeds.

Since the iCalendar spec allows for a CATEGORIES element, this approach shouldn’t be necessary. But not all calendar apps allow you to tag events in this way. Outlook does, but Google Calendar, Live Calendar, and Apple iCal don’t.

Fortunately we can scribble in the margins. I first used that phrase in an InfoWorld story about a feature of the Internet’s Domain Name System called the TXT record. Although it is possible to define more specific record types, it’s hard to get everyone to agree to use them. So developers have historically “scribbled in the margins” of the DNS. And we can do the same with iCalendar.

PS: The title of that InfoWorld story was actually Filling in the Margins, which wasn’t what I wrote and which I never liked. The title I wrote was Scribbling in the Margins, and I used it for the blog entry that introduced the InfoWorld article. I’ll have that entry back online soon, along with the rest of my archive from that era. But meanwhile, when I search for the title using doublesearch, I notice an interesting point of comparison between Google and Bing. It’s been over a month since that blog archive went dark, and Google has now evidently forgotten about it. But Bing remembers. I don’t have any special insight into how Bing works, but I’ll be interested to see how long it keeps remembering.