Getting people to agree on a single ontology has always a problem in the Semantic Web research. There are two schools of thinking. Some people believe that in the future all ontologies will be defined by some kind of standard bodies or special interest groups. Some others believe that there will be many different ontologies flowing around, and standard ontologies will emerge as the result of an “evolution” process — i.e., good ontologies will get used and bad ontologies will be forgotten.
I think the latter is more likely to happen than the former. The new tag service of the Technorati website is a good example. Here is a short description of the service from a Slashdot post:
Technorati (a search engine for blogs) has a new ‘tag’ service. If your blog tool of choice uses Categories, has a RSS/Atom feed, and pings technorati, then you’re done. If not, you can add tags via a new tag markup. The twist is that Technorati is working with Del.icio.us (a social/sharing bookmark manager website) and Flickr (a social/sharing photo web site) to read their tagged content! So Flickr pictures, Del.Ico.us bookmarks, and blog posts all on one page! Here’s an example result for the tag Toronto. There is some documentation as well. One current limitation is that there is no way to do tag intersection as with del.icio.us (i.e. http://del.icio.us/tag/toronto+food ) like http://www.technorati.com/tag/toronto+Food. Tagging (also know as Folksonomies) was the topic recently on Slashdot: Folksonomies In Del.icio.us and Flickr.”