Adobe ACROBAT 3D Manual page 246

Reviewing documents with additional usage rights
By including additional usage rights in a PDF document, you can invite Adobe Reader 7.0
users--in addition to Acrobat users--to participate in document reviews. (Adobe Reader
7.0 is a free download, available from the Adobe website.) Additional usage rights, such
as commenting rights, are document-specific. Acrobat 7.0 Professional or Acrobat 3D
adds commenting rights to the review PDF document when you use the wizard to initiate
an email-based or browserbased review. You can also add commenting rights to a PDF
document by choosing Comment > Enable For Commenting In Adobe Reader. When a
PDF document with commenting rights opens in Adobe Reader, it includes a Document
Message Bar that provides instructions, and the appropriate toolbar opens.
Note: Participants must have email capabilities to review PDF documents that include
additional usage rights.