In light of recent security breaches, I'd say this is a bad idea. Heck, even if it weren't for the recent breaches, I think the biggest problem here is that there are press releases about it.
CIA: "Say, FBI, why don't we make a site where all our secret agents can talk to each other about top secret stuff?"
FBI: "Sounds great! Let's tell EVERYBODY!!"
I'm going to bet that no sensitive data will ever be entered on that site. It could just be a way to find malicious hackers. Basically they'll just set up the site and wait for the hackers to come.