I read a lot of articles in pdf form (grad student) and would like to make annotations on them. I've been trying to do this in Preview (in snow leopard), but even making a couple of annotations radically increases the file size to a point where this is using up a lot of disk space. Using the reduce file size when you save reduces the file size but massively reduces the quality. Are there any other free programs that people recommend that allow one to make highlights/annotations that can be seen in other pdf viewers without massively increasing file size in the way that Preview does? Also, if it was possible a program in which you had the option to email a clean version of the file (i.e. without the annotations), that would be great. Any recommendations would be appreciated!