4.1. Introduction
Tagging provides a detailed description of the content of a file, which makes subsequent searches easier.
Tags are attributes that are applied to files and add additional information to them (metadata).
Including metadata is particularly useful for those types of files (image files, audio files, etc.) that contain no text apart from that in the file name. Tags provide an additional description that will make subsequent searches much easier.
Therefore, tags will be really helpful when searching for information stored in devices, as they provide a detailed description of the structure or contents of a file. They will also enable performing a joint search for all those files that share a common element (e.g. a key word), even if they are not all stored in the same directory in the hard disk.
For this reason, operating systems such as Windows or MacOS have included a tagging function for more than a decade. Nevertheless, this feature is not widely taken advantage of by users, which in most cases do not even know it exists. This is, however, a really useful function that makes it possible to organize files in the hard disk and find them later in a very easy way, with no need for browsing folders. In fact, file explorers in most operating systems enable showing files using tag categories instead of showing them in folders (the usual default way).
Using tags is not only restricted to the private arena in the hard disk or in a user’s cloud storage space. Social tagging, also known as folksonomy, involves using tags on all kind of information on the Internet (images, audio files, video files, documents, etc.). By doing so, content is enriched and more precision is provided to the information that may be found on the Internet. This a cooperative classification using descriptive tags, without hierarchies, which is highly useful for Internet search engines.
In this sense, many social networks offer their users the option to search for markers that are linked to specific tags, and a content ranking is performed according to the number of users that tagged it. These are precisely the web services -particularly Twitter, Facebook and Instagram- that made hashtags popular; a hashtag is a tag that includes one or several linked words preceded by a hash sign (#). Hashtags play a very relevant role in the process of indexing and searching for contents on the Internet.