(continued from previous page)
"A critical mass of users might be reached where it would make as much sense to go into a gigantic tag cloud as it would to go into a search engine," Hill said. "It's an intriguing idea, but it is probably pretty far off."
Others fear that tagging systems may be hijacked by large corporate interests to the point where their value is lost or diluted.
One Flickr group objected when Yahoo bought the service and promptly announced that all members would be required to have a Yahoo account by sometime next year. Primarily, the group is worried that Yahoo will take their registration information and sell it to advertisers.
"Yahoo is trying to use all its different services to expand its user base," said Ville Oksanen, who is spearheading the protest. "If the company wants to keep customers happy, they should make it possible for Flickr customers to stay (just) Flickr customers."
Such sentiments are not uncommon among tagging communities, whose members can be passionately protective of the systems they use. Because of the value they add to information available to everyone, many see tags as one of the rare kinds of metadata large numbers of people have an incentive to create.
"It's the small element that individuals use for their self-interests," said "Smart Mobs" author Howard Rheingold, "that aggregates into something that returns value that nobody put into it individually, but everybody put into it."
Butterfield noted that more than two-thirds of all Flickr images have been tagged by members and can be quickly sifted out of the digital haystack by someone who has an idea what they're looking for. For example, fans of Nevada's Pyramid Lake could search on Flickr and discover that 80 images in the database are currently tagged by users with the term "Pyramid Lake."
Flickr is often cited as an emblem of tagging's success--especially so since it was purchased by Yahoo. But countless other sites, blogs and services have adopted the practice. Other sites that rely heavily on user-created tags include the social bookmarking service Delicious, the community blog MetaFilter and the blog search site Technorati.
The open-source, free encyclopedia, Wikipedia, defines folksonomies as a "
"I've got about 400 to 600 diaries a day, and you've got this crush of information and people clamoring to organize it," said Markos Moulitsas, founder of political blog Daily Kos. "It's a serious problem trying to categorize the amount of information on the site. There are millions of words. How do you organize it?"
The answer came earlier this month with the introduction of tagging on the site. "Unlike categories, which force people to fit their content into a small number of content groupings, tagging allows registered users to categorize not just their own diaries, but those of anyone else's on the site, with as many keywords as necessary," Moulitsas informed Daily Kos' readers with its tagging debut on Oct. 10.
Technorati, a site that indexes blogs, is trying to elevate tagging to the next level. CEO David Sifry explained that his company had recently begun allowing people to tag not only specific blog entries, which had been possible since January, but also to tag entire blogs. Thus, he said, readers can now divine more context about blogs, especially when multiple users tag a site and do so with multiple tags.
A blog might be tagged with the keyword "nanotechnology," for instance, but because individuals might also assign one blog with tags like "biotech" or "bioinformatics" and another with "cyberlaw" or "antitrust," it gives searchers information at a glance that can tell them specific things about that site.
"You immediately get to slice and dice what's going on right at this moment," Sifry said, "in different communities about that topic."