In the discussions about tagging, the words of those who are actually wrestling with this behemoth can be a salutary reminder of just how demanding are the challenges of programming for a folksonomy.
Michal Migurski is the technology head at Stamen, a San Francisco design and development studio which focuses on interactive projects and which is behind Mappr. In a brief posting about Louis Rosenfeld's discussion of folksonomies vs controlled vocabularies, Migurski says:
His point about synonyms is a great one, though, and is pointedly ignored in Clay Shirky's rah-rah response. Folksonomies are unlikely to evolve synonyms for the simple reason that people will usually choose just one of the many synonyms available. For example, self portraits on Flickr are usually tagged with me (15,396 photos) or selfportrait (2,150 photos), but who tags their photos with both? Right. So the overlap just isn't there to be able to infer that these two terms are synonymous, just like people tend to use one preferred name for a place with names in many languages, or one preferred name or nickname for a person in particular contexts. We just happen to be in the early stages of a project that hopes to use folksonomies and user-generated meta-data to make sense of free form conversation, so this is going to turn into a bear of a challenge.

