Not open source but with a free tier: www.breakdown-notes.com. Disclaimer: my project.

You should check out www.breakdown-notes.com. (disclaimer: my project). Only feature missing is code highlighting.

Well not exactly. It would be best described as a mix between MS one-note and MS Visio and Powerpoint (coming soon).

Collaboration by saving and sharing maps / notes using github gist is something I plan to make pretty soon.

Collaboration as in simultaneously working on the same map in some form or the other is something I have been thinking about, but really have little idea about implementing yet.

Well, It's a buffalo breaking down your notes into manageable pieces.

Mmm... I'm not sure it works.

What would you suggest instead? I think it looks well designed and clean, and just as acceptable as any of the other myriad animal-based logos.

I'm not a graphic designer, so I can't tell you what would work, but as a potential customer I can tell you that one doesn't.

Thanks for taking a look. can I ask what you expect after leaving your email ? Would you expect a newsletter about more features, new examples etc ?

great feedback, I get now how the pointer can be confusing, will change that very soon. I will also take a look at a clearer 'to the map!' I have had more feedback about this, and made some changes, but apparently not good enough. Thanks!

Thanks! hope it helps and good luck with the exams.

those are some cool looking diagrams... Something to aim for I have been thinking about using canvas because like you point out, its faster. However I had not worked at all with the canvas and new something about d3.js and svg. d3.js allowed me to use some dragging / events, which I could not have build myself when i started out with this project. That was simply what tipped me in to going with svg. To late to change now...And although there are times when speed is an issue when using the map, its got more to do with some inefficient programming from me.

Thanks a lot! I am working on selecting a print region to export a map as pdf. Will look into adding a feature to export as an image. What for you would be the benefit of of exporting as image instead of as pdf ?

PDF is great if you want to print but nothing beats the simplicity of a PNG for displaying on a web page or inserting into a Word document.