This document discusses the principles behind creating a distributed calendar system using syndicated data feeds. It describes how calendar events are structured differently for humans and computers. The key principles are: data structure, which involves representing events in a standardized machine-readable format; data transformation, which means converting between human-readable and machine-readable representations; and pub/sub syndication, which allows calendar data to be published to and subscribed from distributed hubs while maintaining reference to the original source. The goal is to build a system where calendars can be aggregated and recombined while still maintaining control over the original data.

1. rethinking the community calendar a case study in fourth r principles Jon Udell Berkman Center December 7, 2010 http://jonudell.net

2. where’s the data?

3. here’s data!

4. <?xml version="1.0" encoding="utf-8"?> <rss version="2.0" xml:base="http://cyber.law.harvard.edu" xmlns:dc="http://purl.org/dc/elements/1.1/"> <channel> <title>Berkman Luncheon Series Events</title> <link> http://cyber.law.harvard.edu/views/events-upcoming/947</link> <description> Events</description> <item> <title> [Dec 7] Rethinking the community calendar: A case study in learning and teaching Fourth R principles</title> <link> http://cyber.law.harvard.edu/events/luncheon/2010/12/udell</link> <description> &lt;p&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Tuesday, December 7, 12:30 pm&lt;br /&gt;Berkman Center, 23 Everett Street, second floor&lt;br /&gt;&lt;/strong&gt;&lt;strong&gt;RSVP required for those attending in person (&lt;ahref=&quot;mailto:rsvp@cyber.law.harvard.edu&quot;&gt;rsvp@cyber.law.harvard.edu&lt;/a&gt;)&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;This event will be &lt;ahref=&quot;../../../../../interactive/webcast&quot;&gt;webcast&lt;/a&gt; <?xml version="1.0" encoding="utf-8"?> <rss version="2.0" xml:base="http://cyber.law.harvard.edu" xmlns:dc="http://purl.org/dc/elements/1.1/"> <channel> <title>Berkman Luncheon Series Events</title> <link> http://cyber.law.harvard.edu/views/events-upcoming/947</link> <description> Events</description> <item> <title> [Dec 7] Rethinking the community calendar: A case study in learning and teaching Fourth R principles</title> <link> http://cyber.law.harvard.edu/events/luncheon/2010/12/udell</link> <description> &lt;p&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Tuesday, December 7, 12:30 pm&lt;br /&gt;Berkman Center, 23 Everett Street, second floor&lt;br /&gt;&lt;/strong&gt;&lt;strong&gt;RSVP required for those attending in person (&lt;ahref=&quot;mailto:rsvp@cyber.law.harvard.edu&quot;&gt;rsvp@cyber.law.harvard.edu&lt;/a&gt;)&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;This event will be &lt;ahref=&quot;../../../../../interactive/webcast&quot;&gt;webcast&lt;/a&gt; <?xml version="1.0" encoding="utf-8"?> <rss version="2.0" xml:base="http://cyber.law.harvard.edu" xmlns:dc="http://purl.org/dc/elements/1.1/"> <channel> <title>Berkman Luncheon Series Events</title> <link> http://cyber.law.harvard.edu/views/events-upcoming/947</link> <description> Events</description> <item> <title> [Dec 7] Rethinking the community calendar: A case study in learning and teaching Fourth R principles</title> <link> http://cyber.law.harvard.edu/events/luncheon/2010/12/udell</link> <description> &lt;p&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Tuesday, December 7, 12:30 pm&lt;br /&gt;BerkmanCenter, 23 Everett Street, second floor&lt;br /&gt;&lt;/strong&gt;&lt;strong&gt;RSVP required for those attending in person (&lt;ahref=&quot;mailto:rsvp@cyber.law.harvard.edu&quot;&gt;rsvp@cyber.law.harvard.edu&lt;/a&gt;)&lt;/strong&gt;&lt;br /&gt;&lt;strong&gt;This event will be &lt;ahref=&quot;../../../../../interactive/webcast&quot;&gt;webcast&lt;/a&gt;

5. technologists: thou shalt publish rss feeds website publishers: we hear and obey users: why can’t we make sense of calendars?

6. the blog syndication network publish aggregate subscribe rss rss atom atom

7. the blog syndication network What is the Ob of Nebraska? The Platte. publish aggregate subscribe What is Ann Arbor of Texas? Austin. rss rss What is the RSS of calendars? iCalendar. atom atom the calendar syndication network publish subscribe aggregate ics api syndication hubs ics ics ics ics

8. annarbor,mi honolulu,hi san diego,ca atlanta,ga placerville,ca fredericksburg,va berkeley,ca bellingham,wa troy,ny keenenh barcelona,spain evansville,in falls church,va ferndale,mi myrtle beach,sc greenville,sc brattleboro,vt menlo park, ca Santa Rosa,CA ithaca,ny sunbury-on-thames,uk liverpool,uk baltimore md providence ri sonora,ca new boston,nh ottawa,on Perkasie,Pa polkcity,ia prescott,az cambridge,ma guelph,on saskatoon,sk snoqualmie,wa alameda,ca westbountiful,ut toronto,on virginiabeach,va westborough,ma west lafayette,in huntington, wv what these are what these are not syndicated networks of events free services running in the azure cloud open data feeds based on open source code invitations to help build the data web centrally-managed databases of events destination sites

9. a menlo park hub hub stats: events by source

10. events at stanford

11. a stanford feed in the menlopark hub Eventful Stanford’s iCalendar feed Upcoming Redwood City’s icalendar feed

12. a stanford feed in a menlo park site Eventful Stanford’s iCalendar feed Upcoming Redwood City’s icalendar feed

13. elmcity principles BEGIN:VCALENDAR PRODID:-//Google Inc//Google Calendar 70.9054//EN BEGIN:VEVENT DTSTART:20101006T113000Z SUMMARY:-Rain date for AP Env. Sci. trip to Monadnock data structure transformation hub syndication

14. what people see what computers see what computers need to see or or or to read, print, and interact with information to enable people to read, print, and interact with information to enable data to flow and recombine why?

15. principle of data structure How we describe calendar events: “Jon Udell: Rethinking the community calendar, Berkman Center, Tues Dec 7 12:30“ How computers understand calendar events: DTSTART;TZID=Eastern Standard Time;20101207T123000 SUMMARY:JonUdell: Rethinking the community calendar LOCATION:BerkmanCenter DTSTART;TZID=Eastern Standard Time;20101207T123000 SUMMARY:JonUdell: Rethinking the community calendar LOCATION:BerkmanCenter DTSTART;TZID=Eastern Standard Time;20101207T123000 SUMMARY:JonUdell: Rethinking the community calendar LOCATION:BerkmanCenter DTSTART;TZID=Eastern Standard Time;20101207T123000 SUMMARY:JonUdell: Rethinking the community calendar LOCATION:BerkmanCenter

16. principle of data transformation Laws of arithmetic Laws of data <dtstart> <parameters> <tzid>EST</tzid> </parameters> <date-time> 20060102T120000</date-time> </dtstart> Date: Dec 7, 2010 Time: 12:30PM Zone: Eastern = DTSTART;TZID=EST; 20101207T123000 = =

17. two-way vs one-way transformations Laws of arithmetic Laws of data <dtstart> <parameters> <tzid>EST</tzid> </parameters> <date-time> 20060102T120000</date-time> </dtstart> Date: Dec 7, 2010 Time: 12:30PM Zone: Eastern DTSTART;TZID=EST; 20101207T123000

18. principle of pub/sub syndication syndication hubs

19. sounds like computer science! data structure data transformation pub/sub syndication one-way hashing i’m not a geek, why do i care?

20. 2006: jeannette wing

21. jeannettewing’s manifesto “To reading, writing, and arithmetic, we should add computational thinking to every child’s analytical ability. It is a universally applicable attitude and skill.” R1 Reading R2 Writing R3 Arithmetic R4 ??? computational thinking 21st-century skills digital literacy network mastery systems thinking

23. Phil Libin: “The basics of asymmetric cryptography are fundamental concepts that any member of society who wants to understand how the world works, or could work, needs to understand.”

24. “We posted weekly.pdf to the website. Isn’t that good enough?”

25. monday night chess club Keene Sentinel: Monday night chess club, 6:30 PM, Best Western Hotel Eventful.com: Monday night chess club, 6:30 PM, E.F. Lane Hotel The chess club doesn’t know how (or why) to produce an authoritative data feed about itself The newspaper doesn’t know how (or why) to consume such a feed

26. missing concepts structured data can be represented in many ways some representations of data are best for people, others for computers machine-friendly data can syndicate without loss of fidelity data feeds (and items) have globally unique names (urls) urls enable the “small pieces loosely joined” effect urls pass data “by reference” rather than “by value” when data syndicates from an url, the owner/publisher controls it

27. why is this hard?

28. not just calendars

29. links