Today's thing is tagging. The idea that someone can label any book, blog entry, anything with any label can be both accessible and annoying. As a librarian searching Amazon, I find it a bit frustrating. Although, it has gotten a bit better over the years. I even read that the term for social network tagging is called Folksonomy. The people determine what labels an entry get. For a lot people who didn't go to the library or were shown how to search in library catalogs, I can understand how such tagging evolved. Even the Library of Congress were behind in how subjects were labeled leaving archaic or terms that fallen out of favor, making it difficult to find books.
For instance, a reader of Anime Insider complained he couldn't find all of the anime DVDs when he typed in the term "anime". If he typed in Animation-Japan, this person would. But no one I know calls in animation from
The Anglo American Catalog dictates how items are catalogued in its MARC record. The culture changes so rapidly. I can understand why libraries shouldn't submit to quickly, but the young users (those we know use the library) don't use the subject headings librarians use. Keyword searches sometimes help with that social tagging mentality. Then there are people that give some items esoteric or obscure tags.
I'm sure the tags I use for my blog entries are a bit much, but I know I don't use LOC subject headings. Until then, keep reading.