These are the terms I have collected so far:

Tagging & Social Tagging

Tagging: Tagging is an open way to assign tags or keywords to resources or items (e.g., web pages, movies or books), in order to describe them. This enables the later retrieval of the resources in an easier way, using tags as resource metadata. As opposed to a classical taxonomy-based categorization system, they are usually non-hierarchical, and the vocabulary is open, so it tends to grow indefinitely. For instance, a user could tag this blog as social-tagging, research and blog, whereas another user could use web2.0, social-bookmarking and tagging tags to annotate it.

Social tagging: A tagging system becomes social when its tag annotations are publicly visible, and so profitable for anyone. The fact of a tagging system being social implies that a user could take advantage of tags defined by others to retrieve a resource.

Tag cloud: In order to enable visual browsing, social tagging tools typically provide an interface model known as tag cloud. When users access the information in these structures, it is presented in the form of a cloud consisting of the most popular tags, where the larger is the font size of a tag, the more popular it is on the site. Typical tag clouds have between 50 and 200 tags, and tag weights are represented using font sizes or other visual clues. In addition, tags can be sorted in alphabetical, size-based or random order, and users can usually customize clouds with different fonts, layouts, and color schemes. These structures are particularly useful for browsing or information discovery, because they provide a visual summary of the content in the collection. More information on Wikipedia: Tag cloud.

Social Bookmarking & Social Cataloging

Social bookmarking: Delicious, StumbleUpon and Diigo, amongst others, are known as social bookmarking sites. They provide a social means to save web pages (or other online resources like images or videos) as bookmarks, in order to retrieve them later on. In contrast to saving bookmarks in user’s local browser, posting them to social bookmarking sites allows the community to discover others’ links and, besides, to access the bookmarks from any computer to the user itself. In these systems, bookmarks represent references to web resources, and do not attach a copy of them, but just a link. Note that social bookmarking sites do not always rely on social tags to organize resources, e.g., Reddit is a social bookmarking approach to add comments on web pages instead of tags. The use of social tags in social bookmarking systems is a common approach, though. For more information, see: Social bookmarking and List of social bookmarking sites on Wikipedia.

Social cataloging: They are quite similar to social bookmarking sites in that resources are socially shared but, in this case, offline resources like music, books or movies are saved. For instance, LibraryThing allows to save the books you like, Hulu does it for movies and TV series, and Last.fm for music-related resources. As in social bookmarking sites, tags are the most common way to annotate resources in social cataloging sites.

Folksonomy & Personomy

Folksonomy: As a result of a community tagging resources, the collection of tags defined by them creates a tag-based organization, so-called folksonomy. A folksonomy is also known as a community-based taxonomy, where the classification scheme is plain, there are no predefined tags, and therefore users can freely choose new words as tags. A folksonomy is basically known as weighted set of tags, and may refer to a whole collection/site, a resource or a user. A summary of a folksonomy is usually presented in the form of a tag cloud.

Personomy: Personomy is a neologism created from the term folksonomy, and it refers to the weighted set of tags of a single user/person. It summarizes the topics a user tags about.

Simple Tagging & Collaborative Tagging

To the best of my knowledge, these two terms were first coined by Gene Smith, in the book Tagging: People-Powered Metadata for the Social Web. Previously, Thomas Vander Wal referred to them as Narrow Folksonomy and Broad Folksonomy.

Simple tagging: users describe their own resources or items, such as photos on Flickr, news on Digg or videos on Youtube, but nobody else tags another user’s resources. Usually, the author of the resource is who tags it. This means no more than one user tags an item. In many cases, like in Flickr and Youtube, simple tagging systems include an attachment to the resource, and not just a reference to it.

Collaborative tagging: many users tag the same item, and every person can tag it with their own tags in their own vocabulary. The collection of tags assigned by a single user creates a smaller folksonomy, also known as personomy. As a result, several users tend to post the same item. For instance, CiteULike, LibraryThing and Delicious are based on collaborative tagging, where each resource (papers, books and URLs, respectively) could be tagged (therefore annotated) by all the users who considered it interesting.

For more information on simple and collaborative tagging, see my previous post: What are social tags?

Share/Save

1. What is Tagging?: As an introduction, the book offers an interesting overview on tagging, letting you discover what it is and its advantages.
2. The Value of Tagging: Why do people tag? Why does a website/intranet need a tagging system?
3. Tagging System Architecture: You will learn that a tagging system involves users, resources and tags in it. Moreover, the relations between them and their features are also presented.
4. Tags, Metadata, and Classification Systems Using tags as metadata, and its differences with a classical taxonomic system.
5. Navigation and Visualization: Advantages of a tagging system for navigation and visualization of a website’s content, showing some new stuff like tag clouds. In this chapter, geotagging is also presented.
6. Interfaces: Some tips on implementing a user-friendly interface for a tagging system. How to ease users to tag a resource, recommending or without recommending tags, how to separate tags (spaces, commas, etc.), and much more.
7. Technical Design: Some technical tips, such as designing the database for a tagging system, and using the open-source tagging plug-in FreeTag to ease this work.
8. Appendix A – Case Study: Social Bookmarking: A brief history and some other ideas on social bookmarking sites.
9. Appendix B – Case Study: Media Sharing: Tagging for rich media, such as images and videos.
10. Appendix C – Case Study: Personal Information Management: How to manage personal information with tags.

Strongly recommended!

Share/Save

For example, if you are visiting a paper in repositories like ACM or Springerlink, a new button will appear in your address bar in Firefox bar, indicating you can save it with Zotero. This way, you can collect the sources of your interest in Zotero. But, unlike a usual bookmark, it collects the corresponding metadata, and so the paper title, authors, publication year, etc. will be stored as metadata. After saving the references, you can access Zotero and see all the papers you have previously saved, edit them, and add the desired tags to ease its subsequent retrieval.

But that’s not all. It also allows you to create citations from these references, and even a BibTeX file with the selected references. Really interesting for researchers. Try it!

Share/Save

The messages sent to Twitter also tend to be tagged by users, and so it’s easier to know what’s the sender talking about. Tags are identified in Twitter as those words preceding a # sign. For instance, in the message “It’s sunny today #weather #london” the tags determine the message is talking about the weather in London.

Taking advantage of the tags annotated by users in Twitter, #hashtags offers an easy and friendly interface to monitor the usage of a tag and discover its trend for the last month. For instance, the use of the tag #obama seems to be really variable.

Share/Save

Share/Save

But I have a complaint on its labeling system, since it is not as friendly as I would like. Its labeling system is somehow analogous to a categorization system where folders are used, and is so far from a free tagging system like Delicious. Before including a message in any label, it is necessary to create it, unlike with tagging. Additionally, a list of labels is available on the left (or right, if you configure it) bar. This list could become unmanageable as it grows!

I would prefer to be able to add any existing or non-existing tag to a message, in order to ease its subsequent retrieval. If I only have a message or 2 messages for a topic/idea, I will not create a label for it, but I would possibly add the tag if I could. On the other hand, Gmail could show a tag cloud. It would be interesting!

I would like to know: why not a free tagging system for Gmail? Hope to see it soon

Update (April 9, 2010): Google added a ‘nested labeling’ approach, confirming that it is very similar to a folder-based system.

Is there any difference among Gmail’s ‘nested labels’ and a classical folder-based e-mail organization? The only difference seems that classical systems usually limit including e-mails into just one folder, whereas Gmail’s labels allow multi-foldered organization.

Share/Save

A tagging system becomes social when these tags are publicly visible, and so profitable for anyone. A user could take advantage of tags defined by others to retrieve a resource, e.g. a web site.

Tagging systems can be categorized into two types, as stated by Thomas Vander Wal:

• Narrow systems (aka simple tagging): Only the owners of the resource add tags to it. For instance, Flickr can be considered a narrow tagging system, where only the user uploading an image/photo tags it.
  

  Simple tagging

• Broad systems (aka collaborative tagging): All the users can tag a resource, not only its author. Generally, tags are defined by resources’ users, and as a result of many users tagging the same item, a weighted set of tags is available for each resource. For instance, Delicious, as a social bookmarking site, is a broad tagging system, where each resource (URL) could be annotated (tagged) by as many users as considered it interesting.
  

  Collaborative tagging

As a result of many users tagging resources, social tagging sites present a tag cloud. A tag cloud is simply a list of the most popular tags in the site. Tags in this list usually have different font sizes, where the bigger font size the more resources it has in it. The following image shows a tag cloud on Delicious, where noticeably blog and design tags are the most popular in the site.

An example of a tag cloud from Delicious, retrieved 9 February 2009

Share/Save