A tag is a tag, the end of a rope literally translated from English. English-speaking programmers have introduced this word in the meaning of "message subject". Thus, tags are tails in a sea of textual information; by pulling the desired tail, you can easily pull out the desired text content.
Tags can be called a legacy of thematic library catalogs. They actually serve the same purposes as their predecessors from the pre-computer era: they help you navigate with ease in a huge amount of information. They represent a short, in two or three words or a phrase, a description of the essence, topic of any publication on the Internet - text, video, photograph.
In today's virtual space, it is no longer possible to do without tags. News sites, for example, have existed for many years, while they are updated several times a day, turning into a monstrous chaotic accumulation of various information. The content of such sites is classified in different ways, most often by the authors of the publications, but readers of the news column are more often interested in the essence of the news, and not in the individual style of the author.
In addition, different correspondents can write on the same topic. Therefore, it is most convenient to resort to thematic classification to find all the notes related to any incident, regardless of who published them and when. In recent years, on many similar sites, such a classification of texts is required, and for greater orderliness there are fixed lists of tags, the author only has to choose from them suitable for his publication. Reasonably placed tags make it much easier for readers to find the information they are interested in, but they add popularity to the authors, because the easier the text is, the more people will read it.
For the convenience of users, there is a so-called "tag cloud". It is also a list of the most common, popular tags used on the site. It is called a "cloud" because it often visually resembles an image of a cloud. The more often the site texts are marked with a certain tag, the larger the font with which this tag is written in the "cloud" becomes. With such a simple yet effective technique, the "tag cloud" becomes one of the most convenient navigation tools within the site.
On social (aka collective) open servers, each user can come up with their own tags. In some of them, photos and posts of different users can be combined through the same tags. In others, there is a so-called "search by interests", which are essentially the same tags, only they characterize not one text or one photo, but the entire content of a personal page. Using these opportunities, a wide variety of people can find new acquaintances with whom they share some common interest: be it numismatics or love of skydiving.
Tags are needed in order to classify information of any kind by meaning.
