I am currently letting friends and family spellcheck my thesis written with LaTeX.
Since my markup is macro-heavy and not all of them have ever used another editor but MS Word, I cannot let them work with the source files directly. 

What is the best way for them to review the PDF and send me comments, so that I can quickly integrate them back into my .tex files?

Some of them have Adobe Acrobat at work and can send me annotated PDFs, but at least 50% of the time of fixing the changes is searching the exact position of the missing comma or mistake.

Is there a (preferably cross-plattform) solution that would make their and my life easier?