The world of information organization is shifting paradigms — from categories to tags.
In the traditional world (the files and cabinets, papers and folders world) everything was neatly classified into a single folder or category. But this did not scale well. If you were looking for a long lost article, and were not sure which category you would have put it back then, its probably going to be hard to find it.
Categories/folders are good in places where there’s a unique identifier to each item — for instance, a social security number, or a library catalog ID. But the classic example where folders break down are your bookmarks. The Internet and search engines have changed the way we deal with information. When I see a web page, there are many thigns I associate it with.
Filing it into a single folder is not reliable (because the thing that popped up first in my head when I filed it, may not be the first that pops up in my head when I’m searching for that page again). Its also not very expressive — how would you file a page that deals with both culture and politics.
For a while, directories such as [[http://dir.yahoo.com/|Yahoo's]] or [[http://directory.google.com/|Google's]] or [[http://dmoz.org/|DMOZ]] tried to deal with this problem by trying to place each website in a hierarchy of categories. This did not scale — there is too much manual labor involved, there is no unique procedure, different people might expect the same page to be in different categories and so on.
Then came along tagging. Tags allow you to associate multiple attributes with any single item. This is much more expressive than the category mapping. Tags also make searching and sharing information easier. The real popularity of tags is driven by the large number of web applications supporting tags these days. Here’s a brief list:
* [[http://del.icio.us | Del.icio.us]]
* [[http://mail.google.com | Gmail's labels]]
* [[http://43things.com | 43 things]]
* [[http://43places.com | 43 places]]
* [[http://myweb2.search.yahoo.com/|Yahoo! MyWeb 2.0]]
* [[http://flickr.com | Flickr]]
* [[http://technorati.com | Technorati]]
* [[http://www.furl.net/index.jsp | Furl]]
and many many more.
BTW, here’s a [[http://trutag.rubyforge.org/|cute little app]] that lets you work with your tags across a lot of different websites. I think we’ll be seeing more tools like this in the future — that aggregate and analyze tags across your blogs, photos, bookmarks, emails — to help you find and organize your information.
We live in a brave new world :-)