What are social tags?
I decided to start this blog with a brief review on what are social tags. Tags are an open way to assign keywords to a resource, in order to describe it and later retrieve it in an easier way. As opposed to a classical taxonomic 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, blog and web2.0 whereas another user could use weblog and tagging tags to annotate it.
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.
- 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.
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.