Flickr allows both the public and private storage of your photos. Any user uploading an image on the site can adjust the access control his image and thus determining who will have access to it. These settings provide access to several categories: private, friends, family or public. You can also make adjustments for any private group.
Most Flickr users make their public photos accessible to everyone: thus creating a large database of photos sorted by categories. Other users can leave comments on any image they have the right to see, and add tags.
To protect copyrights, Flickr offers photographers the opportunity to protect their photos by a Creative Commons license.
Excerpted from "Tout sur le web 2.0» (Capucine Cousin, Collection CommentCaMarche.net, Dunod, 2008)