In Adobe Acrobat Pro you can do things like put little sticky notes in PDFs, highlight text, and create bookmarks. I have found this very useful for learning. In school you learn better when you put your notes right in the textbook. Some of the material is now delivered in pdf form.
However I've switched to Linux. I find that there are several programs that can read PDFs, but they can't do all those useful things I just mentioned.
Are there any linux programs that can? I found a program that converts pdfs to ps format. If I convert a pdf to a ps file, are there programs that let you do these kinds of things?