Hoteldruid is designed to manage weekly or daily rental of house apartments or hotel rooms. It uses a PostgreSQL, MySQL, or SQLite database as a backend. Reservations can be assigned to rooms automatically with user-defined rules. Pages with forms to check availability for Internet sites can be created. It supports multiple users with a privileges system. Documents and invoices can be printed, saved, and emailed.
Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.
SAGU, which is a portuguese acronym for "Sistema Aberto de Gestão Unificada", was originaly designed to automate all of what that happens between a student and their Educational Institution. This relationship happens at the academic, financial and administrative levels, and SAGU has subsystems dedicated to these levels. SAGU can be tailored to fit the needs of any Educational Institution.