Social networking for spies?

The media is terribly naive:

Of course, the material on A-Space is highly classified, so it won't be available for the public. Only intelligence personnel with the proper security clearance, and a reason to be examining particular information, can access the site. The creators of A-Space do not want it to be used by some future double agent such as Jonathan Pollard or Robert Hanssen to steal America's 21st-century secrets.

Security clearances are not a protection against sociopaths like Hanssen, and men like Pollard who are absolutely convinced in their own mind of the righteousness of their cause which runs counter to the laws and policies governing classified materials. You can investigate them until hell freezes over, and wire them up to all sorts of machines to test the honesty of their statements, but the chances that you'll catch them are slim to none. The best that you can hope for is to convince them to not violate the terms of their security clearance by making the penalty for willfully compromising intelligence to a foreign country not only consistently enforced, but terribly painful for those who get caught doing it.