You can use Acrobat 8 to apply usage rights to PDFs, in order to distribute the PDFs for Review and Commenting workflows to Reader 8 users. This includes the option to print comments. This is possible in Acrobat 8 using the “Document and Markup” option in the print dialog itself, and if the “Print notes and pop-ups” option in the Commenting preferences in Acrobat is enabled.
However, in Reader there are no Commenting preferences, so the users have no way to enable printing of comments even if they select the “Document and Markup” option from the print dialog.
There is a registry key in Acrobat that controls the “Print notes and pop-ups” option in the Commenting preferences. If you set the following key in the Reader registry, then the comments are printed:
[HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\8.0\Annots\cPrefs] "bprintCommentPopups"=dword:00000001