"Just as the internet allows users to create and share their own media, it is also enabling them to organize digital material their own way, rather than relying on pre-existing formats of classifying information," states the report. "Tagging is a kind of next-stage search phenomenon -- a way to mark, store, and then retrieve the web content that users already found valuable and of which they want to keep track."
The report also points out that tags are explicitly social. For instance, users can classify their photos with tags on a site like Flickr -- by giving photos tags like "beach" or "park." Others who then search the site for pictures of a beach will see the photos that consumers have tagged with the label -- a system that makes tagging "a classic example of bottom-up building of categories instead of top-down imposition of categories."
For the report, Pew asked 1,623 Web users whether they had ever categorized or tagged online content. Twenty-eight percent said they had, and 7% said they did so the day before being surveyed.
Who is likely to tag? Not surprisingly, they're "classic early adopters," states the report. They're more likely under 40, and tend to have higher incomes and education levels.
While Pew has no trending data because it hadn't before questioned people about tagging, the report cites stats from Hitwise showing that sites that enable tagging, like Flickr and Del.icio.us -- both now owned by Yahoo -- are gaining in popularity. Flickr accounted for .029% of Web visits for the week of Jan. 13, up from less than .012% the week of Oct. 22, while Del.ic.ious accounted for .0036% of visits the week of Jan. 13, up from less than .0005% the week of Oct. 22.