I haven't tried to use it but what I've read in the comments here you also ask for email address.
Confidential, maybe. Anonymous, unlikely.
I don't log any data other than the date besides what you put in the fields. I also don't connect the email address to the listing, it just goes onto a mailing list.
For now it is confidential, though I'm not sure how to reconcile the idea of an API with confidentiality - even when anonymity is involved. Perhaps I should just change it to 100% anonymous?
You'll soon face spam issues though. what's your spam strategy?