4.3 Document Features. The Software may contain features and functionality that appear disabled or "grayed out" (the "Document Features"). The Document Features will only activate when opening certain PDF documents that have been created using corresponding enabling technology available only from Adobe ("Keys"). You agree not to access, or attempt to access, disabled Document Features or otherwise circumvent the permissions that control activation of such Document Features. You may only use the Document Features with PDF documents that have been enabled using Keys obtained under a valid license from Adobe. No other use is permitted.
So, some of the following are illegal:
If the PDF is given:
Windows:
AREnable
http://sourceforge.net/projects/arenable/
However it violates the LEGAL user agreement of Adobe
Windows/Linux
http://www.foxitsoftware.com/
Adds a small note that it was done with this program
Windows
PDF-Xchange viewer (free)
http://www.docu-track.com/home/prod_user/pdfx_viewer/
Linux
flpsed - a Postscript and PDF annotator
http://www.ecademix.com/JohannesHofmann/flpsed.html
flpsed is a WYSIWYG PostScript2 annotator. You can't remove or modify existing elements of a document. But flpsed lets you add arbitrary text lines to existing PostScript 2 documents. Added lines can later be reedited with flpsed. Using pdftops, which is part of xpdf one can convert PDF documents to PostScript and also add text to them. flpsed is useful for filling in forms, adding notes etc.
If I can create the PDF I can use the following techniques to allow to write PDFs using Acrobat Reader:
\documentclass[dvipdfm]{article}
\begin{document}
Test PDF document with annotations.
\special{pdf: ann width 3.0in height 36pt
<< /Type /Annot /Subtype /Text /Contents (This is a /Text Annotation that looks like a sticky note.) >>}
\end{document}
Put the \special{} in a \marginpar{} if you want it to appear in
the margin of your document, etc.
You can also write
\usepackage[pdftitle={Title},pdfsubject={Subject}]{hyperref}
in your preamble.
Have a look at the hyperref manual.
http://multivalent.sourceforge.net/
Windows/Linux
pdftk - A handy tool for manipulating PDF
http://www.accesspdf.com/pdftk/
use it to:
Merge PDF Documents
Split PDF Pages into a New Document
Rotate PDF Pages or Documents
Decrypt Input as Necessary (Password Required)
Encrypt Output as Desired
Fill PDF Forms with FDF Data or XFDF Data and/or Flatten Forms
Apply a Background Watermark or a Foreground Stamp
Report on PDF Metrics such as Metadata, Bookmarks, and Page Labels
Update PDF Metadata
Attach Files to PDF Pages or the PDF Document
Unpack PDF Attachments
Burst a PDF Document into Single Pages
Uncompress and Re-Compress Page Streams
Repair Corrupted PDF (Where Possible)
