I've been thinking a lot lately about how we organize information online and what that means for online marketing. In my opinion, there are two discrete ways to organize information. First, there is a hierarchy - an outline of information with parent-child relationships between categories or items. For instance, if "beverage" is the parent, children would be milk, water, or a daiquiri. All daiquiris are beverages, but not all beverages are daiquiris (for most of us). A good example is the Dewey Decimal system. Books are housed via a set system of categorization based on hierarchy. The benefits of such a system is the use of a common language (continuity, predictability) and the visual appeal (relationships easy to access). However this system is rigid and does not react to changes over time.
Now, there is a new system of categorization. Tags are a "type of meta-data involving the association of descriptors with objects," which basically means categories associated with items after the fact or on a case-by-case basis. Tags are flexible, work across cultures and languages, can be used by the author or a reader, and assists with search. Examples of tag use include del.icio.us and Flickr where users can organize and share bookmarks and photos, respectively. The detriments to using this type of organizing system is that there is no relationship between items (no parent-child hierarchy) and no relationship with the rest of the language (homophones, for example).
It seems to me that we are going to have to rectify the old faithful taxonomies with the Web 2.0 ones. But how is this possible? They may be mutually exclusive; the use of common categories, for example, specifically excludes the use of tags conceived by others. I suppose that might be a back-end system of suggesting tags to users based on what others have already used, thus providing a higher instance of identical tags. But we are many years out from a system intelligently designed enough to understand the intricacies and nuances of English (much less other languages).
Please share any ideas in the comments section. If Web 1.0 is a one-way process of providing content to the reader (thus, hierarchical) and Web 2.0 is a two-way dialogue (using tagging), then perhaps Web 3.0 is where users are connected to other users and where everyone is a content producer and content consumer - perhaps this is when some resolution will occur. Online marketers are uniquely positioned to make this change and the person or persons to get in front of this problem will make a ton of money, believe me.