Am I right in saying that if you put a Smoothwall box in place to filter traffic, then the amount of spyware and other rubbish that makes it through from these rubbish websites will be reduced?
How exactly does that work? I mean, if a user goes to a legitimate site that has rubbish injected into it somewhere, does Smoothwall block access to the site completely or just the bad bits?
Generally just the bad bits. Depends on how the site is infected and which problems are encountered.
you can also turn on AntiVirus, which has a significant performance cost, but will further reduce the level of any infection.
To clarify what Tom has said, you can turn on antivirus on the appliance which will scan all web traffic, in addition to any running on the client.
This then gives you another layer of defence.