Profile: Flickr's Photo Synthesis

Flickr Architect Cal Henderson provides a snapshot of the popular photo-sharing Web site and its beginnings.

Flickr's catchphrase, "The best way to store, search, sort, and share your photos," seems like an arrogant assertion for a two-year-old Web site still in beta. But Flickr boasts more than 2 million users and countless technology critics who agree. They all think it's the best photo-management and -sharing application on the Web, not to mention an excellent example of Web 2.0 functionality.

Flickr Architect Cal Henderson attributes his company's success to a winning combination of unique services that sets it apart from its competitors. Essentially, Henderson says, Flickr is a social network based around photo sharing that relies on collaborative metadata, aggregation of community content, and open APIs.

Flickr is a crossbreed of social-networking and photo-sharing sites. Users develop relationships with other users. They can display photos in sets, or albums where a single photo can appear multiple times, and groups that are organized around special interests. They can also add photos to Flickr Web pages, RSS feeds, e-mails, and blogs for their friends and family to view.

To create a safe photo-sharing environment, Flickr offers unique permissions-based functionality. Flickr's creative commons, or license agreements, are "a natural extension" of a social network, says Henderson. Users govern their own data by licensing content when it's uploaded to the site, stipulating from the outset who can view their photos and how they're used.

Almost all of Flickr's creative commons encourage open content. Consequently, more than 80 percent of the 93 million photos on Flickr are available for public use. Henderson emphasizes that community-based content is essential to Flickr's progress. He proclaimed, "Upload photos, and let the world see."

Users rally around this community-based content. They add information to their own photos and other users' photos by tagging them, or marking data with words that indicate to search engines what's there. This information accretes around the photos as collaborative metadata. Users "can look at their friends' photos, tag them, comment on them, add to their friends' sets and groups, or switch up photos," Henderson explains. He sums up the process like this: "You aren't just viewing other people's data; you're actively changing it."

Tagging photos with metadata allows Flickr to aggregate its community content. Community aggregation is a powerful organizational tool and a testament to the success of bottom-up hierarchies, Henderson says. By conducting a simple keyword search, users can easily organize and reorganize images. For example, Henderson clarifies, users "can look up all the photos that people have uploaded and tagged with 'San Francisco,' instead of just looking at their own photos of San Francisco." Flickr allows users to create different and appealing ways to perceive the group data, or as Henderson labels it, the "global collection of photos."

In addition to end users, developers can also benefit from Flickr technology through its open APIs. "Lots of people have built hundreds of applications on top of Flickr," Henderson says, and they've come up with interesting, and sometimes commercially useful, applications that add value to Flickr. And these same applications create more discussion about Flickr, helping recruit new users. Henderson proudly affirms that Flickr's popularity has "all been grass-roots, community-based growth."

Not surprisingly, this unique social-networking and photo-sharing hybrid has evolved quite a bit since its conception, and no one has been more amazed by Flickr's wild success than its creators: a small team of Vancouver-based developers formally known as Ludicorp. When Ludicorp was established, its mission was to produce a massively multiplayer online game called "Game Never Ending" (GNE). Money was tight in the early 2000s, and Ludicorp launched Flickr in February 2004 as a way to generate money for GNE production costs. It soon became apparent that Flickr was incredibly popular, so Ludicorp shelved the game and began working on Flickr full time.

Flickr was first modeled on the core technology behind GNE, a realtime messaging environment. Ludicorp also made photos available on Web pages in addition to the instant messaging services. According to Henderson, instant messaging required that lots of people were online at the same time—for this reason, the asynchronous nature of Web pages was more advantageous. Eventually, the realtime environment was abandoned.

It was around this time—March of last year—that Yahoo! acquired Flickr. The biggest change for Henderson was leaving Canada and moving to Sunnyvale, Calif., where Yahoo! is based. Henderson reports other changes too: "Yahoo! has given us the resources to buy necessary hardware, keep paying the staff, [and] come to work and have an office." He continues, "They know about building big Web sites, and we're in their datacenters. We no longer have to run into the datacenter whenever anything goes wrong, and pull out screwdrivers!"

So, what's on Flickr's six-month roadmap? For the most part, this remains a secret. But Henderson hinted that more features and mapping capabilities will be built into Flickr, in "new and exciting ways."