To me, a scenario like that means that people have disengaged from their work. Blocking social media sites will not change it. It will simply result in them finding different avoidance strategies.

We allow social networking tools at my org, and I'm 99% sure that we don't have anything that constitutes abuse (and, if we do, I'm an abuser, as I have Twitter open all day and I check it every hour or two, and post one to six ttweeta a day). My feeling is that, if we were to block Twitter and Facebook, the 90% or higher of our staff who either don't check it at work or don't need to wouldn't care all that much, and, of the 10% who do, we'd be blocking mission-supporting activities.

We also use web-blocking software, a decision that is justified by it's role in blocking spyware-laden sites. We recently reconfigured our filters (which had been set up by my predecessor), and went with no blocking or "warn, but allow to continue" on a lot of things that had previously been set to block. The only sites that aren't clearly threats that we agreed to continue blocking with pornographic sites. My take is that IT has no business determining for staff what is business-related and what isn't (I blogged pretty extensively about this here: http://techcafeteria.com/blog/2009/04/21/the-roi-… but that blocking pornography is probably more of a favor to our staff than an act of censorship. It's far more often unintentionally loaded than intentionally. Mind you, I've also worked places where the reverse is true…