Really great post and great project!
I'm a bit afraid of "post signatures" though. I hate to browse forums where users use signatures. It just seems such a waste of space, specially those that completely abuse it. I would suggest to not support signatures, but ya, not sure if others agree with me (haven't read the comments, sorry if someone already mentioned this).
Btw, I'm posting this using chainbb.com, which is now my prefered way of interacting with steem.
The nice thing is that if people use the system, it'll allow everyone else to hide/show them based on their personal preference. If they didn't use the system, it'd just be part of their post and there wouldn't be a way to hide them.