I noticed that on my Mac, the program Preview allows you annotate PDF documents. If I open up the same PDF file in Adobe Reader on the PC, I can see the annotations in the Comments pane, but I cannot create new ones. I'm guessing that both programs are using some standard defined in PDF documents for annotations.
I'm wondering if there is any good utility that is similar to Preview on the Mac, which will allow me to make annotations. Since Preview is free on the Mac, I'm hoping to find a similar free solution for the PC.
I noticed on the comparison page of Adobe Acrobat, that the Pro and Pro Extended versions allow you to make a document annotatable by Adobe Reader users. If a product simply enables this feature on a PDF document, it would be a good solution as well, since then I can use Adobe Reader for annotations.