I'm not sure that it's entirely a heartwarming idea that Virgin are running a secret tool to inspect four out of every ten customer's internet streams to spot "illegal" files:
Jon James, Virgin Media executive director of broadband, said, “Understanding how consumer behaviour is changing will be an important requirement of Virgin Media’s upcoming music offering and, should they become law, the Government’s legislative proposals will also require measurement of the level of copyright infringement on ISPs’ networks.
“Detica’s CView technology potentially offers a non-intrusive solution which enhances our understanding of aggregate customer behaviour without identifying or storing individual customers’ data,” he added.
It's not entirely clear how having someone look at what you're doing online is "non-intrusive". Even if the intention is to keep it anonymised, there's a question mark over how anonymous you really can make such studies.
It's also not clear how, exactly, this data will detect 'illegal' files - by which we're presuming they mean unlicensed files. How - if the data is anonymous - would Virgin even begin to be able to tell if the data they're looking at is being used with or without permission? Do they have some sort of magic detection box?