Question 1: How to set up websense to prevent workers from posting on SO (and all related sites), without blocking them from viewing answers?
Question 2: How to make SO (and all related sites) pop up a captcha everytime it is visited from the office intranet? Is it possible by appending to the URL?
If people weren't allowed to post answers, there wouldn't be any answers. If your employees are spending so much time on SO that it's hurting their job, I'd suggest your resolution should be administrative, not technical. If they're just giving back to the community with occasional answers, then is it really a problem?