text: is tagging in a social network really useful? there are many sites that let you search web pages based on the tags people give to them. but everyone may tag the same thing very differently, the tags may only be meaningful to the person who come up with them and may have nothing to do with the meaning of the contents. i believe that searching based on tags by other people is mostly meaningless. agree? the idea is that you might put a tag on a document that totally doesn't contain the word you associate with the link.  for instance, a page about building muppets might contain a pic of david bowie because of that labyrinth movie.  the page might not contain any reference to him, and the picture might not be named after him, but when i "tag" that page with his name, you'll be able to find that rare pic of him.  i would guess that any one person's tags are pretty well meaningless, but when you aggregate them all together, meaning emerges.