I think it is probably a bad idea to rely on the expensive patent process to protect open source. Isn't it better to make the software available and visible so that it can be clearly established that it is prior art, i.e. already known by all, when someone tries to patent drawing rectangles on the screen, or whatever?
The summary doesn't mention this, but a part of what Open Invention Network does is exactly that. Apparently patent examiners only look in certain places for prior art, and OIN can help you publish your work there.