Hundreds of encodings have been developed, each for small groups of languages and special purposes. As a result, the interpretation of text, input, sorting, display, and storage depends on the knowledge of all the different types of character sets and their encodings. Programs are written to either handle one single encoding at a time and switch between them, or to convert between external and internal encodings.

Part of the problem is that there is no single, authoritative source of precise definitions of many of the encodings and their names. Transferring of text from one machine to another one often causes some loss of information. Also, if a program has the code and the data to perform conversion between a significant subset of traditional encodings, then it carries several megabytes of data around.

The Unicode Standard provides a single character set that covers the languages of the world, and a small number of machine-friendly encoding forms and schemes to fit the needs of existing applications and protocols. It is designed for best interoperability with both ASCII and ISO-8859-1, the most widely used character sets, to make it easier for Unicode to be used in applications and protocols.

The Unicode Standard is in use today, and it is the preferred character set for the Internet, especially for HTML and XML. It is slowly being adopted for use in e-mail, too. Its most attractive property is that it covers all the characters of the world (with exceptions, which will be added in the future). The Unicode Standard makes it possible to access and manipulate characters by unique numbers (that is, their Unicode code points) and use older encodings only for input and output, if at all.