While I still hope to find a buyer to keep the service going, I am providing the source code in the event that it does not work out. It is fairly straightforward php code, so all you have to do to use it is unzip the file below and upload it to a web server. Navigate to index.html and it will work just as it did on the full website.
Good luck. If you have any trouble or questions, please feel free to contact me. I will try to find a way for you to export any signatures that you have already created. Also, if you are interested in taking on the hosting and domain of Social Sig, please let me know as well.