Clepsydra is a free web application for managing a numeric data collection (it's pictures centric, but can also store other type of content).
It allows you to share your documents over the internet. So you don't have anymore to send your pictures by email or to check ten different web sites to look at the pictures of the same wedding. Different people contribute by adding their pictures or documents and the other users can look at them, search for them, view a satellite map containing them or display a slide show. Instead of trying to collect all the pictures from you friends and family, you can just manage them in a central server, and publish them to everybody easily in one shot. But if you want to look only at the pictures you took it's real easy too. The goal is that each one is not running it's own gallery system, but instead one gallery system is used by everybody.