Ask a Geek: What is tagging?

Answered by Merlin Mann, freelance writer and consultant.
A group of people with different skin colors putting sticky notes with words on them into the shape of a mouse pointer.

Tag and click. Alex Nabaum

Answer: Tagging is the act of assigning your own keywords to things online—photos, blog entries, bookmarks—so that you can easily categorize, locate, and share them in the future. One of the best examples is, which lets you save web bookmarks to a page on the site instead of to a file stashed away on your computer. This way, you can access them from anywhere and let other people see what sites you like. So if you saved to your collection and tagged it with “science, tech, magazine,” anyone who clicked on the “science” tag would see it, along with any sites anyone else had tagged “science.” There are no rules for coming up with tags, so results can be unpredictable, but that’s part of the fun, and most are pretty intuitive anyway.

Tagging is also a great way to find stuff related to topics that interest you. Missing life in the Bay Area? Go to the photo-sharing site, and click on “San Francisco” to bring up hundreds of photos of the city.

Some sites, including, Flickr, and the goal-sharing site, also generate RSS feeds for specific tags, so you can easily follow certain topics, such as “recipes,” “mac” or “webdesign.” You can even subscribe to friends’ lists to see what they’re surfing, or you can generate custom feeds for them—tag certain items “for Madeline,” and she can check out all the sites that you’ve bookmarked just for her.

  • Merlin Mann lives in San Francisco. He is the creator and editor of and the popular productivity tips site He’s currently co-writing the book Life Hacks for O’Reilly.

This story has been updated. It was originally featured in the August 2005 issue of Popular Science magazine.