December 2006 Pew Internet survey finds that 28 percent of Internet users have tagged or categorized such content online as photos, news stories, and blog posts. On a typical day online, 7 percent of Internet users say they use tags to categorize online content.

The idea behind tagging is simple and straightforward, but its ramifications are complex and multifarious. For the better part of a decade, the primary way to categorize, retrieve, and discover information on the Internet was through search engines' automated algorithms, originally topically challenged and highly imprecise. Of course, this structured organization opened the door for SEO (define) as a means to influence ranked results.

Tagging has quickly gained popularity because it allows humans to bring a layer of collective, topically pertinent, and intuitive organization to what otherwise would be a discombobulated heap of semi-aggregated data, such as reverse chronological archives or authors pages, and the like. With its inherent keyword-rich, interlinked, topically concatenated structure, tagging content, images, and videos has become yet another readily adaptable SEO tactic; one worthy of inclusion in link-building strategies.

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