Taxonomy goodbye, Folksonomy hello! The difference between the two is usually explained with variations around the word ‘formality’.
Taxonomies imply standards of information for the purpose of searching, retrieving … essentially the science of classification; very boring! Folksonomy is similar but has only one standard, open-ended categorization. Here is an example that might clear things up.
Assume, for a moment, that Taxonomy is as form with structured fields, lines and many “If you selected yes above…” directions. In contrast, Folksonomy would be a blank piece of paper. On this paper you can right down words that you see fit. What you end up doing is tagging and categorizing without being restricted. Since “great minds” think alike, people of your “greatness” would be lead to your information rather effectively.