The Yahoo!-owned website Flickr is the world's most popular photo-sharing website, claiming a repository of three billion images, all of which are submitted by the site's members. Basic accounts are free and offer the ability to upload, sort, and tag photos in innovative ways. Tagging of faces, objects, and places is possible, and albums of various types can be created.

Galleries are laced with social networking features. You can add friends and family and give them special access to photos, and they can comment on your uploads or even tag a particular area of the photo with a message.

Flickr offers a variety of licensing options, including all the Creative Commons licenses, so you can decide who can use your images and in what ways. You can also choose from several privacy levels to control who can see the images to begin with.

Recently, the site added video sharing to its list of features. Free account holders can upload up to two standard definition videos per month, while Pro users can upload high definition videos.