the original hypertext system and wikipedia

Jakob Voss

The original hypertextsystem and Wikipedia

We were promised Xanadu

draft slides for discussion

presented atFachhochschule Hannover

June, 14th 2010

Jakob Voss: The original hypertext system and Wikipedia draft slides for discussion. June 14th, 2010

Agenda

● Wikipedia● WWW● Xanadu● Comparision● Discussion


Jimbo Wales in: Robin Miller: Wikimedia Founder Jimmy Wales Responds. Slashdot (2004-07-28)

“Imagine a world in which every single person on the planet is given free access

to the sum of all human knowledge. That's what we're doing.”


Wikipedia

● Wiki-based open content encyclopaedia● Quick editing● Versioning● Hypertext (pages, links, discussion pages...)● Open Content license (CC-BY-SA)

● Founded 2001 (by accident!)● More than 200 language editions,

10 of them with > 500.000 articles


Wikimedia

● Infrastructure● donations and volunteers● Wikimedia foundation and local chapters

(among them Wikimedia Germany)● MediaWiki software

● Largest general reference work(s)● Other Wikimedia projects

● Commons, Wikiquote, Wikisource …● Projects only partly connected


Some more Wikipedia features

● Redirects and disambiguation● Media inclusion via Wikimedia Commons● Templates (Infoboxes…)● Categories (Thesaurus)● Interwiki links (mono-directional)● Extracted data (DBPedia, Personsearch…)● ...


Wikipedia revision history

http://en.wikipedia.org/w/index.php?title=Gdańsk&oldid=221829087 (“Permalink“)

http://en.wikipedia.org/w/index.php?title=Gdańsk&action=history


Internet Archive snapshotshttp://web.archive.org/web/*/http://en.wikipedia.org/wiki/Gdańsk

http://web.archive.org/web/20080626090544/http://en.wikipedia.org/wiki/Gdańsk


Information Management: A Proposal (1989)Tim Berners-Lee

WWW

Bild

: ca

ptso

lo@

flic k

r


World Wide Web

● invented in 1989 by Berners-Leeto connect distributed databases

● limited to a mono-directed graph, no history● original concepts reintroduced: collaboration

(“Web 2.0”), data integration (“Semantic Web”)


Hyperlinks

Ted Nelson

ted.

hype

r lan

d.co

m

A File Structure for the Complex, theChanging and the Indeterminate (1965)


“HTML is precisely what we were trying to PREVENT – ever-breaking links, links going outward only, quotes you can't

follow to their origins, no version management, no rights management.”

Ted Nelson's Computer Paradigm, Expressed as One-Liners (1999)


Gary Wolf: The Curse of Xanadu. Wired Issue 3.06 (1995)

“Xanadu, a global hypertext publishing system, is the longest-running vaporware

story in the history of the computer industry. It has been in development for

more than 30 years.”


Concepts of Xanadu

● Deep links to document fragments● Transclusion● Versioning● Docuverse (parallel texts)● Strechtext (levels of detail)● Rights management


Some properties of Xanadu

(4) Every user can search, retrieve, create and store documents.

(5) Every document can consist of any number of parts each of which may be of any data type.

(6) Every document can contain links of any type including virtual copies ("transclusions") to any other document in the system accessible to its owner.

(7) Links are visible and can be followed from all endpoints.

(8) Permission to link to a document is explicitly granted by the act of publication.

Xanadu FAQ (2002-04-12)http://xanadu.com.au/general/faq.html#2

http://xanadu.com.au/general/faq.html#2


Some properties of Xanadu

(4) Open editing

(5) Compound documents

(6) Transclusion

(7) Bidirectional links

(8) Reuse and linking allowed

Wikipedia

✓ partly (on-topic only)

✗ very limited

✗ very limited

✓ yes (inside one wiki)

✓ yes


Differences

Wikipedia● Open content only● Nobody is paid● Reuse and mixing

encouraged but difficult to track

Xanadu● Any content● Micropayment● Reuse and mixing

easy and tracked


Common properties

● Both are “closed systems”● In Wikipedia backlinks, version history etc. do only

work inside a Wiki (not even between languages) References to external resources are plain text only

● In Xanadu there is no “outside of the system”

● Both support mixing and changing of content● Wikipedia solves the rights (but does not track all)● Xanadu is based on mixing and linking of content


How can we do better?We were promised Xanadu!


Limitations of the WWW

● Structured data ✗● Collaboration ✗● Backlinks ✗● Changes ✗● Split & Merge ✗


Limitations of the WWW

● Structured data ✓ Semantic Web ● Collaboration ✓? “Web 2.0”● Backlinks ✗● Changes ✗● Split & Merge ✗ “Mashups”, “Copy & Paste”


Limitation: Backlinks

● How do you easily get the resourcesthat link to a given resource?

● Possible solutions● HTTP Referrer ✗● Notify link targets (Pinkback etc.)● Harvest links (crawler)

● Open Questions● Not integrated into basic Web infrastructure ● No open link databases to query!


Limitation: Changes

● How do you track changesin documents on the Web?

● General solution● Versioning and Diff

● Practical solution● Adding history to the Web

● Open questions● Which standard?● How to diff specific file types (see: split & merge)


Adding history to the Web

● URL identifies the currentversion of a Web resource

● Some create new URLs for each new version● Old versions may also be available elsewhere


Adding history to the Web

● Memento Web Project (work in progress!)● Additional HTTP-Header● Typical requests

● “get the resource as it was at time X”● “get the list of changes between X and Y”

● Related techniques● Feeds of changes (ATOM, RSS) and OAI-PMH


Limitation: Split & Merge

● How to track merge and split on the Web?● Problems

● Compound documents and document parts● Clone & Merge instead of Copy & Paste● Existing standards (Xpointer etc.) failed

● Existing solutions● Distributed Version control systems (git, hg, bzr…) ● OAI-ORE (Object Reuse and Exchange)


Deep links in Xanadu

“An identifier for any portion/span of text (of whatever version) can be constructed. This is in

fact the main innovation of Xanadu.”


version 1

version 2

version 3

version 4

text A

text F

text C

text D

text B

text E

text G

time

mergechange

merge

change

change change

version 5

change

changechange


text C

text D text E

branch

changechange

parallel text

Types of changes

text A

text B

parallel text

change


“All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act

towards one another in a spirit of brotherhood.”

„All human beings are born free and equal in dignity and rights.“

„Alle Menschen sind frei und gleich an Würde und Rechten geboren.“

extract

translate

„All human beings are equal.”

extract (sense changed)


Types of changes (to discuss)

● Some practical examples● Simple extract (quote)● Modfied extract (thumbnail, abstract … )● Translation, review

● Some general types● branch (sth. “new”)

– Split (to branches that may be joined again)● modify (expand, remove, same document)● merge/combine (transclusion, aggregation)

– Insert into an aggregation

the original hypertext system and wikipedia

Technology

wikipedia draft slides

xanadu draft slides

yesallowed jakob voss

articles jakob voss

wikipedia backlinks

wikipedia wiki

discussion pages

wikipediadraft slides