Phorm (formerly 121 media) has been in the news a lot recently.
1) Got caught running a secret program to track the browsing habits of 18,000 customers in 2006.
2) Unveiled a new advertising model: Mr. X googles “job,” Phorm picks up on this, and then Mr. X gets Weight Watcher ads in spaces that Phorm has bought in popular websites. [this, I think, is basically what they were doing in 1) but now they’re taking extra privacy precautions]
This improves upon the most popular model today, where A Weight Watcher’s ad is on CNN.com, even though Mr. X doesn’t goes to BBC.com, instead.
The top 3 british isps have already signed up – account for 70% of broadband users in UK
[* the British have an enlightened attitude towards the security/privacy gradient http://news.bbc.co.uk/1/hi/uk/6108496.stm]