Noidman encompasses a few different projects:

• Noid.rb -- Noid.rb is a Ruby library for the Noid ARK software
• Noidman -- an ARK identifier management web application written in Ruby on Rails
• Arkham -- a cleaner, faster, and more robust refactoring of Noidman, including full REST web service interface
• ArkhamFuture -- a fully-implemented version of the ARK spec, based upon Arkham

The Noidman projects are Ruby- and Rails-based libraries and web applications for creating, managing, validating, and resolving persistent identifiers. They are built around the Archival Resource Key identifier schema, with the Noidman and Noid.rb projects using the Noid (nice opaque identifier) tool released by the California Digital Library, but may be generalized for other types of identifiers.