[dspillett]

> Vodafone has had something similar for mobile for years, no?

Virgin too, I had one of their PAYG SIMs for a while and you had to opt in to have the filter turned off (which was a faf IIRC).

The content that it blocked for me was the national lottery web site (presumably gambling was one of the filtering criteria), but the holding page presented when you visited a blocked site carried adverts which amusingly enough at the time were for what was essentially sex chat lines... I've still got a screen grab of it somewhere.