Robin Good: Kapsul is a web-based platform for the collaborative creation and editing of contemporary art images, and other art-oriented, visual artworks.
Kapsul allows you to easily add any image, text, PDF, video or artist information to any Kapsul, either manually or via a dedicated bookmarklet.
From the official site: "Kapsul is a platform for collaboratively creating collections of images, videos, and texts online.
Kapsul aims to help contemporary art curators, artists, educators, and enthusiasts find, organize, and share elements of visual culture in collaborative units called Kapsuls.
Kapsuls can be used for planning exhibitions, organizing research, making presentations, or publishing soft exhibitions online.
Kapsul is a project of the Kadist Art Foundation, a nonprofit organization based in San Francisco and Paris..."
Kapsul collections can be made "private" or "public". A special "share link" can be used to invite other people who you want to contribute to your collections.
Free to use.
More info: http://www.kapsul.org/