The Tree-Friendly Academic: Whither A Useful Free PDF Editor? 

 I'm a Linux user in need of a quality PDF reader with basic annotation tools, and I need it to be available for free. Think I'm asking for too much? 

 We're at a point where the level of content available online dwarfs our ability to print it all onto paper for examination and notation. As academics, we're expected to sort through volumes of other people's work in order to verify that our own is original, as well as comment, annotate, and on occasion make corrections or forward-references to later works.  

 But despite a boom in computational power and information bandwidth, the software to do this without resorting to printed or copied matter isn't accessible to most students without paying through the nose. Full software suites like Adobe Acrobat aren't necessary for the kind of work academics need to do. There are a few functions that are essential to the task, currently available in commercial software: 

 -Adding and reading notes, whether free-floating or attached to highlighted text 
-The ability to select and copy multi-column text (none of the free ones seem to be able to get this one right) 
-I'd like that when LaTeX creates a link to a footnote or citation, hovering over the displayed link should cause a pop-up box to display the information. 

 I'm a man with big ideas but no time, and more importantly, no budget, to motivate and drive the development and use of a free PDF reader with mild annotation capabilities. I can't resort to the for-pay software available from the school website because I'm running Linux, and I shouldn't have to go to a virtual machine or another computer to do this kind of annotation. Likewise, others shouldn't have to spend hundreds for software where they only need a few simple functions. 

 I suppose the issue is that everyone has their own toys they want included in a PDF editor, which is why the commercial package makes sense. But as academics, wouldn't we be happy with "the basics plus"?