From the about page (now defunct):
Agora Ciudadana is an innovative free software project whose aim is to create a social network for the people, allowing secure and scalable votings via Internet with just your web browser
The project is being driven by Seville, Spain-based Wadobo.
From their project description:
Agora Ciudadana is a social web site where anyone can create or join in an agora. An agora has a set of members which can vote in the agora’s elections either by direct vote or by delegating the vote.
The source code is available on GitHub.
Update: Agora Voting has been discontinued, and renamed and updated as nVotes. In order to access a copy of the old Agora Voting site, view an archived copy.
Additional information and materials about Agora Voting: