If we all had to sign a message to log on to this forum (assuming there wasn't the "stay logged in" option), that would not only be a huge pain in the ass for members experienced with bitcoin and signing messages, but it'd turn away potential members who might not even know how to do it yet and wouldn't take the time to learn just to be a member here--and that would be understandable, since it seems like a lot of newcomers think bitcointalk is a throwback from the 2010 era.

But you know?  Theymos tends to make things extremely complicated (like the merit and trust systems); this idea sounds like something he'd go for if it weren't for privacy and/or security issues involved.  It's definitely not something I'd want to see come to pass.

Also, I agree with the member above who mentioned that OP's response to OgNasty's post is just a wee bit inadequate to spark a discussion.  It would be nice for thread starters looking to get people's opinions to start by giving their own.  Just a suggestion, OP.