My work's internet filter is fairly lax but it does tend to block random Wiki/BBC pages because it apparently contained a banned keyword. E.g. I'm not allowed to look up the iPad on Wiki:
I can get the OcUK shop ok from work, just haven't tried the forums but I think forums will be ok too. However, our IT dept audits every URL, so they can quite easily trace me to being Monserrat on OcUK. Then because everyone writing "lolislam" or "Islam≠race" or "I like bacon" on Facebook automatically gets the sack and goes to jail, the same will happen to me as I'm not the most PC poster

So yeah, any forum logins, I tend not to associate with my work's PC.