Web 2.0 is, in its typical usage, a completely nebulous term. Yet remarkably its boosters will declare that it's all so clear, you idiot - it's "<INSERT THEIR OWN PARTICULARLY DIVERGENT INTERPRETATION HERE>". I've seen this play out in quite a few online and offline discussions, proving to me that it's an amorphous/eye-of-the-beholder sort of term.

Tim O'Reilly and friends were one of the first to widely coin it, so his take obviously deserves attention, yet even it lacks any degree of clarity. Really it appears to be nothing more than a freeze-frame of the web's continuing evolution.

Nonetheless, one recurring attribute of the "Web 2.0" religion deserves attention - Folksonomy, which is the loosely-controlled user-base keyword tagging of content (usually contrasted against the taxonomy of a site like Yahoo, where a central group of annoited ones classify content, albeit really they're just rubber stamping the classification provided by the website owner).

For instance I upload a picture to Flickr, keywording it flower and bee. Now people searching for related pictures can browse amongst pictures of bees, or flowers, or bees and flowers, and see my content amongst everyone elses. del.icio.us follows the same model, with users adding links and meta-data keywords that categorize them. Links can then be searched or related by keyword(s).

Everything old is new again.

In the early days of search engines, the content parsers were really quite dumb - they couldn't read the content of a web site and really figure out what the subject of the page was. As such the META tag was added, allowing website owners to attribute their content with a small, select group of keywords, and those keywords would allow it to choose content appropriate for user searches.

Of course what started as a good idea quickly devolved - nefarious website operators learned to put unrelated, popular terms in their keywords to earn additional hits: What started as a great idea devolved into a tragedy of the commons as more and more people got involved, and they started gaming the system for their own advantage.

The sort of things that work on small-scale, edge sites quickly degrade as they become larger and more important. Already many of the "social tagging" sites are getting overwhelmed with spam and false hits, and of course errors, and more commonly errors of omission, are extraordinarily common on these tagging sites.

Of course for photos there are no other options - we're not at a point where an automated analyzer can look at a picture and determine what it's about, so tagging is the best we've got. However for some attributes, like location, free-text tagging is terribly unreliable, which is why I look forward to the automated GPS tags talked about previously.

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