You guys might like this project I've been working on for the last six months:
It helps you manage your reading by keeping all your PDFs and web content in one place.
It's open source, cross platform (Linux, Mac, Windows, + web) and free.
The main issue I have to focus on right now is explaining why it's so powerful. I'm going to create a video here shortly.
Basically , it supports suspend and resume of reading, text and area highlights, and spaced repetition via Anki.
I'm working on a big new release here shortly and also applying for grants over the next few weeks.
Also, one thing, it's mostly a geek tool and I'm still working on fit and finish and usability.
If it's awesome please let me know. If something is broken, please ALSO let me know - I'll fix it!