Flickr

Flickr is a photo sharing website and web services suite, and an online community platform. It was one of the earliest Web 2.0 applications. In addition to being a popular Web site for users to share personal photographs, the service is widely used by bloggers as a photo repository. Its popularity has been fueled by its innovative online community tools that allow photos to be tagged and browsed by folksonomic means. It hosts over 2 billion images.

Organization

A screenshot of hot tags on Flickr.

Flickr asks photo submitters to organize images using tags (a form of metadata), which allow searchers to find images concerning a certain topic such as place name or subject matter. Flickr was also an early website to implement tag clouds, which provide access to images tagged with the most popular keywords. Because of its support for tags, Flickr has been cited as a prime example of effective use of folksonomy, although Thomas Vander Wal suggested Flickr is not the best example of folksonomy.

Flickr also allows users to organize their photos into "sets", or groups of photos that fall under the same heading. However, sets are more flexible than the traditional folder-based method of organizing files, as one photo can belong to one set, many sets, or none at all. Flickr's "sets", then, represent a form of categorical metadata rather than a physical hierarchy. Sets may be grouped into "collections", and collections further grouped into higher-order collections.

Organizr

Organizr is a web application for organizing photos within a Flickr account that can be accessed through the Flickr interface. It allows users to modify tags, descriptions, and set groupings, and to place photos on a world map (a feature provided in conjunction with Yahoo! Maps). It uses Ajax to emulate the look, feel, and quick functionality of desktop-based photo-management applications. Because of this, Organizr simplifies the batch organization of photos, which is more cumbersome with the normal web interface.

Access control

Flickr provides both private and public image storage. A user uploading an image can set privacy controls that determine who can view the image. A photo can be flagged as either public or private. Private images are visible by default only to the uploader, but they can also be marked as viewable by friends and/or family. Privacy settings also can be decided by adding photographs from a user's photostream to a "group pool". If a group is private all the members of that group can see the photo. If a group is public the photo becomes public as well. Flickr also provides a "contact list" which can be used to control image access for a specific set of users in a way similar to that of LiveJournal.

In November 2006 Flickr created a "guest pass" system that allows private photos to be shared with non Flickr members. For instance, a person could email this pass to parents who may not have an account to allow them to see the photos otherwise restricted from public view. This setting allows sets to be shared, or all photos under a certain privacy category (friends or family) to be shared.

In March 2007, Flickr added new content filtering controls that let members specify by default what types of images they generally upload (photo, art/illustration, or screenshot) and how "safe" (i.e., unlikely to offend others) their images are, as well as specify that information for specific images individually. In addition, users can specify the same criteria when searching for images. There are some restrictions on searches for certain types of users: non-members must always use SafeSearch, which omits images noted as potentially offensive, while members whose Yahoo! accounts indicate that they are underage may use SafeSearch or moderate SafeSearch, but cannot turn SafeSearch off completely.

Many members allow their photos to be viewed by anyone, forming a large collaborative database of categorized photos. By default, other members can leave comments about any image they have permission to view, and in some cases can add to the list of tags associated with an image.