David Anderson QC, the terror legislation watchdog commissioned to report on the state of Britain’s surveillance laws in the aftermath of Snowden’s disclosures, has previously said that internet connection records included storing details of every website visited up to the first forward slash in their address – but not a detailed record of all web pages on a particular site. The internet connection records will also include times of contacts and the addresses of the other computers or services with which the user made contact.
“Under this definition a web log would reveal that a user had visited eg google.com or bbc.co.uk but not the specific page,” said Anderson in his report, A Question of Trust. “It could also of course reveal ... that a user has visited a pornography site or a site for sufferers of a particular medical condition, though the Home Office tells me it is in practice very difficult to piece together a browsing history.”
Given this information logged over time (it's kept for 1 year) by an ISP, would it really be difficult to piece together the browsing history of an individual? (ignoring the other types of information that is either already available to them or they can get further to this)
The only hurdle I can see is differentiating the individual from others at that physical address, but if an analysis of Facebook likes can reveal if I'm gay then I reckon a year's worth of browsing history from one physical address could easily be divvied up into individuals. Even if the number of individuals is unknown.
What have I missed?
Edit: I wrote to David Anderson QC, and he tells me that is a quote from his report and is only stating what the Home Office told him, his opinions are given later in the report. I don't think this changes the validity of the question though, but I don't want to be unfair to him.