You can send notes and audio in various file formats. With the smartpen, you can specify the format in the shortcut definition or at the time you select your content. With Livescribe Desktop, you specify the format at the time you select content.
Pencast is the format used by Livescribe Desktop, MyLivescribe (Livescribe Online), Mobile, iPad, iPod, Facebook, and Google Sites.
Pencast PDF is a new format that Livescribe is introducing with Livescribe Connect. When opened in Adobe Reader X or above, a Pencast PDF can play the audio and display notes in synchronization.