For a long time pdflatex has offered the command \pdfannot for inserting
arbitrary PDF annotations. However, the command is presented in
a form where additional knowledge of the definition of the PDF format is
indispensable. This package is an answer to the – occasional – questions
in newsgroups, about how one could use the comment function of Adobe
Reader. At least for the writer of LaTeX code, the package offers a
convenient and user-friendly means of using \pdfannot to provide comments
in PDF files. Since version v1.1, pdfcomment.sty also supports:

       LaTeX -> dvips -> ps2pdf, LaTeX -> dvipdfmx and XeLaTeX.

Unfortunately, support of PDF annotations by PDF viewers is sparse to
nonexistent. The reference viewer for the development of this package is
Adobe Reader.

License: LPPL

Changes in v2.1:
  
- added support for PDF reply system
    \pdfcomment[avatar=Joe,id=1]{comment}
    \pdfreply[avatar=Bob,id=2,replyto=1]{reply to comment}
  works for pdflatex only!

- added options id,date,timezone

- added support for new icon CrossHairs (Adobe Reader X)

- Bugfix: problem with \pdfmarkupcomment with page break