So - del.icio.us has been bought by Yahoo, (yahoo blog / del.icio.us blog), and everyone has an opinion on tagging.
We'll just reference Stephen Green (who is nice and concise) - Let's say we have a system where people manually assign keywords to documents (tagging) and let's also say that people can run queries against this index of keywords. You can think of such a query as an attempt by the searcher to assign keywords to a document that he or she would like to get in response to the query. The problem is that the person who originally assigned a tag to the document and the searcher who "assigned a tag" to the document are going to be inconsistent, so the searcher won't pick quite the same tag.
This is true. However, it also misses the point. No one ever said that tagging was the answer for search engines (it's clearly not), or that it was superior to keyword searching within documents. However - pictures (what flickr uses tags for) are not documents, and neither are links (what del.icio.us uses tags for).
When considering links and pictures, tagging, and being able to search those tags, is alot more useful than having no tagging. Links and pictures include some metadata, but usually not nearly enough to find a particular one in a pile.
Even if people are internally inconsistent, having the ability to search for a particular photo by inputting something (dimly remembered text) is better than being forced to search by scrolling by date. That's why we think all photo albums should support tags.
Indeed, we think that in the future, certain tags should be added automatically. For pictures, having EXIF data include things like geographical location (by GPS or from cell networks) would be nice.
[Image Credit: Om Malik]
