In the US there is a common carrier defence, however being a conduit does not necessarily mean you cant be held liable (in the UK at least) for stuff carried over your network.
It's more relevant to a 'real' data network where say images of children/pornography are carried (ISPs often have to get disclaimers from the Police/etc when helping with an investigation as it's ILLEGAL to view images - there's no get-out for ISP staff!!!!).