Semantics Through the Tag

Dave Beckett
Yahoo! Inc.

This talk is personal opinion. I am not speaking on behalf of Yahoo!

Slides presented using Slidy by Dave Raggett

Outline of talk


A lightweight process to describe web content using short words called Tags

The Tagging Process


  1. The person performing it, the tagger
  2. The web resource URI that is being described
  3. The date and time of the tagging process
  4. The set of tags used - the tagset

Presenting Tags

Lists of resources for a tag xtech tags

Popular tags : Tag Clouds tag cloud

Suggested Tags post with suggested tags

Automated analysis of tags

bristol tag cluster on flickr


The Big Assumption: a tag is a primary key

Works well on events such as xtech: Technorati, Planet XTech

Emergent Tag Structures


Hierarchy hierarchy of cnf
cnf on delicious


my bundle

Whose stuff is tagged?

Whose Tag is it Anyway?

Ultimately, who cares?

Tags are vocabularies per service - tagonomies

So what are the purposes of tagging semantics?

  1. For people to understand what some use of a tag means.
  2. For computers to gather information about a tag, supporting purpose #1

What does a tag mean to a person?

Ask them? Not scalable.

Look it up in some authority? (dictionary, encyclopedia). Not distributable.

Tagging: Good Things

Tagging: Problems

i.e. the usual human-entered metadata problems

Tagging semantics possible solutions

Tagging Unplugged


popular tags

Going through the tag


Answer: Wiki

Example: raptor tag

top 10 hits for raptor on yahoo search

top 10 hits for raptor on google search


wiktionary raptor

wikipedia raptor


Easy to create

Can record ambiguity and synonyms/prefered names

Microformat compatible:

Semantics from Tagging

Tag raptor links to

Edit this page to add the meaning you meant.

Discuss it if you don't understand the term

Add disambiguation

Wiki is not so good at

The RDF slide

as much or as little as you want





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