Adobe ACROBAT READER 7.0 Manual page 90

Reviewing documents with additional usage rights
If the initiator includes additional usage rights to a PDF document, you can participate in
an email-based or browser-based review, provided that you use the full version of Adobe
Reader 7.0. When you open a PDF document with commenting rights in Adobe Reader,
the Save command and Commenting tools are available, and a Document Message Bar
appears in the document's heading. (See About Adobe PDF documents with additional
usage rights.)