A Folksonomy is an informal flat list of terms. Folksonomies are collected by social tagging in SharePoint, and a user can assign terms to documents, blogs, wikis, or in fact most of the information in SharePoint.

Social tags are metadata that is applied to items in the social networking features that are available in Microsoft Office 2010. For example, you might want to apply one or more descriptive tags to a blog entry.

In some ways, social tags behave similarly to terms in a taxonomy term set; if the value requested is not an existing term or you do not want to use an existing term, Microsoft SharePoint Server 2010 adds a new entry to the keywords in the Group.

Social tags, unlike managed metadata terms, give you more flexibility. Managed metadata can require permission, or an approval process, to add a new term. Unmanaged metadata can be applied more quickly because no approval process is required. Folksonomies do not have the rigid structure or tight control by a select group that taxonomies do, nor do they have the consistency of an organizationally defined taxonomy. They do, however, provide users with the ability to introduce new terms that could enhance the ability to search for and quickly find the best information available on a given topic.

Folksonomies can also inform taxonomies when terms introduced via a folksonomy become incorporated into the organization's taxonomy after appropriate review. In that respect, the taxonomy does not remain static, but can grow and become more current as new terms emerge out of a folksonomy.