I work for a very large national company that has thoroughly blocked almost all the interwebs. I can reliably get on weather sites, wikipedia, and Vanguard (but only because our 401K is through them!), but just about everything else is blocked. Sometimes I can access a website 2 or 3 times and then it is gone (I hope the security team enjoyed my searching for a paella recipe!).
But, miracle of miracles, I can always get to MMM- even the forums- after about a month of heavy use! I can only surmise that there is a fellow mustacian IT guy at work who is keeping it open for the few, the proud.
Thank you, nameless IT hero!