The article reviews the findings and opinions of theorists and researchers who are dedicated to analyzing the phenomenon of folksonomies. We highlight the main definitions of folksonomy, their characteristics, the different types of existing folksonomies, and the differences with traditional indexing using controlled vocabularies, analyzing the advantages and disadvantages of this new model. We conclude that folksonomies can offer great advantages in information retrieval, especially if they are used to complement the indexing using controlled vocabularies