Vienna is a freeware, open source RSS/Atom newsreader for the Mac OS X operating system. It provides features comparable to commercial newsreaders, but both it and the source code are freely available for download. A summary of some of its features: • Subscribe to Atom/RSS news feeds and podcasts • Simple and intuitive user interface • Built-in tabbed browser • Smart folders for organising related feed articles • Custom article display styles • Three separate reading layouts • Blogging integration • Filter the displayed articles • Manual reordering of the subscription list • Full AppleScript support • Localised into several languages