Uhm... yes, this is my guestbook. It's running from Ctrl-C.Club with a tiny PHP guestbook script I made myself (because I was already tired and insecure of the stupid things on almost all those free GB services) which is available on GitHub. Feel free to leave any messages regarding this website or anything else with respect.
In case the iframe doesn't works, try opening it from your current browser tab by pressing this link or wait until the server is up and running. And I also recommend copying your message before sending it in case the CAPTCHA system fails unfairly.