In the interests of journalism I spent an hour this lunchtime browsing the punternet website looking for contact details for Ipswich prostitutes. Other than a couple of sideways glances from colleagues as I filtered through the sites of 40something BBWs (Big Beautiful Women) I didn't encounter any problems.
I was a little surprised that I could surf this sort of thing at work without anyone questioning it (though maybe the editor will pull me aside for a little word later), but it's a good thing professionally that my company doesn't block sites and stop me from doing my job. I bet librarians in the filter-obsessed US would struggle - most of the sites would be blocked by NetNanny or CyberPatrol.
See here for earlier discussion of filtering software.