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 v1.6:
  
- added support for using \pdfmarkupcomment in math mode
  (see: example_math_markup.pdf)

  feature request by: Ross Moore (he also contributed ideas and code)