I am glad you like it!

There is a slider you can set that changes the duration. I fixed it at 1-7-30 days. I probably need to make that feature more visible though. And I'll add in the option to let users set the kill duration.

I do hard-delete the posts once they expire, but I don't know how I could give users a sense of 'security' that it has gone into the void. Do you have any suggestions?