Adobe ACROBAT READER 7.0 Manual page 89

Types of review workflows
In Adobe Reader 7.0, you can review and add comments to PDF documents that contain
additional usage rights. You may receive an email attachment for review in one of the
following types of workflows:
Tracked email-based reviews.
Tracked browser-based reviews. You must have access to a shared server to participate in
this type of review.
In both review workflows, you add your comments to the PDF document using tools in
the Commenting toolbar. However, during an email-based review, you send the document
with comments back to the review initiator via email. In a browser-based review, you
upload your comments to a server.