[daeken]

While I understand the motivation for this, I think it's actually a bad thing. Why? As you said, it's not perfect (and can't ever be), but when you create a service like this, people tend to use it in the way they see fit. If this got big, you'd have people actually using it to send emails that they think wouldn't be forwardable, when a simple copy and paste (at most) will defeat it.

It's a neat project, but it's snake oil that people will buy into. That's bad.