Document management
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Yellow sticky notes
I've tried LyX. It's not bad, but the killer is, as houshuang says, collaborating with other people. It's not simple or slick enough that I can ask my supervisor to set it up to add his comments on a paper. I sent him PDFs for a while, but when I couldn't get the Bibtex references formatted quite right, I gave up and used a word processor. I'd love to see something better in this space.
(I'm not the poster you replied to, I just have a similar view)
from http://www.lyx.org/Features: