As someone who is constantly (it seems) looking for new ways to take notes / todos this is a very cool solution.
Using a get request to write the one-line notes is really nice - though do you handle any sort of auth with this? Can FF be configured to handle that with the shortcuts?
I love the idea of running this at home and being able to access it from anywhere - and it being a simple webpage.
Edit: I just took a look at the source and no, no auth - though for home-network constrained things this could still be cool.
I like the novel approach to it :)