This property can be used to link from a person to the website where they make previews of their works available, or from a manifestation (a track or an album, for example) to a web page where a preview download is available. This property MUST be used only if the content is just available through a web page (holding, for example a Flash application) - it is better to link to actual content directly through the use of mo:available_as and mo:Stream, mo:Torrent or mo:ED2K, etc. Therefore, Semantic Web user agents that don't know how to read HTML and even less to rip streams from Flash applications can still access the audio content.