Quick rundown of what it is. This is a cross-platform network drawing program. And pretty much the only reasonably good one I can find that supports Linux (my OS of choice) and Windows (everyone else's, including my Mabi husband).
Their site is here [link]
It's sort of abandoned but it works nicely, nonetheless. My only real complaint is that layers are disabled in network mode.

Alright, with a little effort I've compiled the latest version of Drawpile for Windows. You can find it here: [link]

I compiled for Linux as well but that's less of a butt and considering the variance in Linux it's more difficult to share. However there were some troubles in it so let me briefly explain what I did, to the best of my recollection.

1) Make sure you have git, cmake, qt4, and zlib installed.
2) Clone the git repo: git clone https://github.com/callaa/Drawpile.git
3) cd Drawpile
4) mkdir build
5) cd build
6) cmake ..
7) nano src/client/CMakeFiles/drawpile.dir/link.txt
8) Add -lz between -lQtCore and -Wl
9) Save (Ctrl+O) and quit (Ctrl+X)
10) make
11a) sudo make install
or 11b) su root && make install
12) For me, it installed drawpilenet.so to the wrong place so I did: ln -s /usr/local/lib/libdrawpilenet.so /usr/lib64 - Good idea? Probably not..

AS A SPECIAL BONUS here's the .desktop file I made for it. Save it to ~/.local/share/applications/drawpile.desktop

[Desktop Entry]
Name=Drawpile
GenericName=Collaborative drawing program
Comment=Draw pictures with others over the network
Exec=drawpile
Terminal=false
Type=Application
Categories=Graphics;2DGraphics;RasterGraphics;